Research Article
Open Access
Unicuspid aortic valve in a patient with Streptococcus bovis endocarditis
Pages 731 - 732
Research Article
Open Access
Beating-heart aortic valve replacement following total arterial revascularization
Pages 730 - 731
Research Article
Open Access
A normally functioning caged-ball mitral prosthesis after 37 years without warfarin therapy
Pages 729 - 730
Research Article
Open Access
Tricuspid valve replacement for carcinoid heart disease to allow liver transplantation
Pages 728 - 729
Research Article
Open Access
Imaging of caseous calcification of the mitral annulus
Pages 726 - 727
Caseous calcification of the mitral annulus is a rare form of periannular calcification that generally appears as a calcified mass with a central echolucent area that may lead to diagnostic errors. The case is reported of a 65-year-old woman in whom a suspicious mass was detected with transthoracic echocardiography performed for dyspnea.
Research Article
Open Access
Eustachian valve endocarditis: a rare complication of automatic implantable cardioverter defibrillator placement
Pages 723 - 725
Eustachian valve (EV) endocarditis is extremely rare and often difficult to diagnose. An extensive review of the English literature has shown no report of EV endocarditis as a complication of the automatic implantable cardioverter defibrillator (AICD). A rare case is reported following AICD placement that was diagnosed by clinical findings of sepsis and positive blood cultures, and supported (using transesophageal echocardiography) by the presence of vegetations attached to the EV. Previously reported cases of EV endocarditis are reviewed, and its significance discussed in the setting of an increased use of AICD.
Research Article
Open Access
Lipomatous tumor of the tricuspid valve: report of a rare case
Pages 720 - 722
The case is reported of a 19-year-old man with cardiac valve lipomatosis which was accidentally discovered during the work-up for an atypical chest pain. Echocardiography detected an immobile mass that involved the base of the anterior leaflet of the tricuspid valve. Magnetic resonance imaging showed evidence of tricuspid valve lipomatosis, a rare cardiac valve tumor. After five months, echocardiography showed that the mass had not grown. To the best of the present authors' knowledge, very few reports exist of cardiac valve lipomatous tumors.
Research Article
Open Access
Delayed aortic regurgitation caused by a right coronary stent protruding into the aorta
Pages 717 - 719
Aortic valve perforation is an extremely rare complication after percutaneous coronary intervention. The case is presented of a 49-year-old male with aortic valve regurgitation secondary to the intra-aortic protrusion of a right coronary stent. The patient had undergone an apparently successful rescue percutaneous transluminal coronary angioplasty with a drug-eluting stent following failed fibrinolysis, but one month later was readmitted for acute pulmonary edema. Further investigations demonstrated new-onset aortic regurgitation. Medical stabilization was achieved and an elective aortic valve replacement and coronary revascularization performed. Intraoperatively, the stent was found to be partially deployed within the aortic lumen, causing perforation to the non-coronary cusp.
Research Article
Open Access
Successful catheter-based valve-in-valve implantation for a regurgitant stentless bioprosthesis
Pages 713 - 716
Catheter-based transapical aortic valve implantation (TA-AVI) in patients with severe stenosis of the aortic valve and with a high operative risk is a new procedure which is becoming established in clinical practice. Aortic regurgitation is not yet a recognized indication for TA-AVI, and to date valve-in-valve (V-in-V) implantation in patients with incompetent stentless bioprostheses has not been attempted. The case is reported of a successful TA-AVI in a regurgitant, uncalcified stentless Medtronic Freestyle bioprosthesis. The position and hemodynamic function of the apically implanted valve were excellent, and the patient's current state of health is good.
Research Article
Open Access
Recurrent infective endocarditis with uncommon Gram-negative Pasteurella multocida and Pseudomonas aeruginosa: a case report
Pages 710 - 713
Infective endocarditis (IE) due to Gram-negative bacteria is a rare occurrence, with a relative frequency of less than 10% compared to that caused by Gram-positive bacteria. Herein is presented the fatal case of a 66-year-old man who had undergone mechanical aortic valve replacement 10 years previously, and developed aortic valve IE after sepsis with Pasteurella multocida caused by a cat bite at the left medial ankle. In addition, the patient suffered five months later from mitral and aortic valve endocarditis caused by Pseudomonas aeruginosa. Recurrent surgical therapy was mandatory. This unique case of recurrent Gram-negative IE shows that the condition must still be regarded as complex and often fatal, despite adequate medical and surgical treatment.
Research Article
Open Access
Results of a propensity score-matched comparison of the Perimount Magna and Mosaic Ultra aortic valve prostheses
Pages 703 - 711
Background and aim of the study: Hemodynamic function and clinical outcomes were compared between the bovine pericardial Edwards Perimount Magna (EPM) and the porcine Medtronic Mosaic Ultra (MMU) aortic valve prostheses. Methods: Between January 2003 and June 2007, a total of 227 consecutive patients was prospectively enrolled, and received either the EPM (n = 125) or the MMU (n = 102) aortic valve prosthesis. The primary study end-point was the mean transvalvular gradient after surgery, at discharge and at six months follow up, as measured echocardiographically. The secondary study end-points were 30-day mortality and major adverse cardiac events (MACEs). Results: The intraoperative transvalvular mean pressure gradients were 9.4 +/- 4.6 mmHg in the EPM group compared to 17.7 +/- 6.7 mmHg in the MMU group (p < 0.001), and these remained essentially unchanged at hospital discharge (11.2 +/- 4.2 mmHg versus 19.1 +/- 6 mmHg; p < 0.001) and at six months' follow up (10 +/- 5 mmHg versus 20 +/- 7 mmHg; p < 0.001). A multivariable risk-adjusted analysis of covariance revealed the MMU valve (p < 0.0001) to be strongly associated with elevated postoperative mean transvalvular gradients during the six-month follow up. In addition, renal insufficiency, concomitant valve surgery and reoperation were identified as being significantly associated with in-hospital mortality (OR 3.3, 95% CI 1.3-8.1; OR 3.7, 95% CI 1.4-9.8; OR 3.3, 95% CI 1.1-10.2, respectively) and major adverse cardiac events (OR 2.2, 95% CI 1.0-4.7; OR 3.7, 95% CI 1.7-8.2; OR 2.7, 95% CI 1.1-7.2, respectively). To further control for selection bias, the propensity score was computed based on the major risk factors of 12 patients. An analysis of covariance model, adjusted for the propensity score, also confirmed the MMU prosthesis to be strongly associated with elevated mean transvalvular gradients during the six-month follow up period (p < 0.0001). Conclusion: The study results clearly demonstrated a favorable hemodynamic function as shown by lower transvalvular gradients of the bovine pericardial Edwards Perimount Magna compared to the porcine Medtronic Mosaic Ultra aortic valve prosthesis.
Research Article
Open Access
Sutureless Perceval S aortic valve replacement: a multicenter, prospective pilot trial
Pages 698 - 702
Background and aim of the study: A European, multicenter, prospective, non-randomized, clinical pilot trial was designed to evaluate the feasibility of the Perceval S sutureless aortic valve prosthesis. A clinical and echocardiographic follow up was performed at the time of hospital discharge and subsequently after one, three, six, and 12 months. Methods: The valve was implanted following sternotomy, extracorporeal circulation (ECC), aortic cross-clamping, cardioplegic arrest, and removal of the native valve. Implantation suturing was not required. Optimal annular sealing was obtained with brief low-pressure balloon dilation. If coronary bypass was indicated, a distal anastomosis was performed first. Between April 2007 and February 2008, 30 patients (mean age: 81 +/- 4 years) underwent aortic valve replacement. The prevalence of pure aortic stenosis was 76.7%, and that of mixed lesion 23.3%. The mean logistic EuroSCORE was 13.18%, and the NYHA class was III and IV in 93.3% and 6.7% of patients, respectively. The implanted valve size was 21 and 23 mm in 37% and 63% of patients, respectively, and 14 (46.7%) underwent coronary artery bypass grafting (11 internal mammary artery, nine vein grafts). Results: The mean aortic cross-clamp and ECC times were 34 +/- 15 min and 59 +/- 21 min, respectively. There was one in-hospital death (3.3%), and three deaths occurred within 12 months of follow up (one death was valve-related, and two deaths were independent of the valve implantation). A total of 28 patients was assessed at one month post-implantation, and 23 after 12 months. No migration or dislodgement of the valve had occurred, but there were two mild paravalvular leakages and two mild intravalvular insufficiencies. Conclusion: The preliminary results of the trial confirmed the safety and efficacy of the Perceval S sutureless aortic valve. In this high-risk subset of patients, shortening the aortic cross-clamp and ECC times may help to reduce mortality and morbidity.
Research Article
Open Access
An alternative option for elderly patients with a small aortic annulus: the 16 mm ATS valve
Pages 691 - 697
Background and aim of the study: The optimal procedure and prosthesis remains debatable for aortic valve replacement (AVR) in high-risk elderly patients in whom the aortic annulus is too small to allow a standard AVR procedure with even the smallest sized bioprosthetic valve available. Herein are reported the early and mid-term results of standard AVR using a 16 mm ATS Advanced Performance (AP) mechanical heart valve. Methods: The medical records of 10 patients (mean age 75 +/- 5 years; range: 64-79 years) in whom 16 mm ATS AP valves had been implanted in the supra-annular position were reviewed retrospectively. Preoperatively, the mean body surface area was 1.46 +/- 0.1 m2 (range: 1.21-1.69 m2); mean logistic EuroSCORE 16.1 +/- 14.6% (range: 4.32-53.2%); mean peak pressure gradient (peak PG) across the aortic valve 98 +/- 28 mmHg; mean diameter of the aortic annulus 19.3 +/- 1.2 mm; mean fractional shortening 37 +/- 10%; and mean left ventricular myocardial mass index (LVMI) 173 +/- 34 g/m2. Results: There were no hospital deaths, and one late death. The postoperative course was uneventful in all cases, except for one patient who developed respiratory failure. The NYHA functional class was improved from 3.0 +/- 0.7 before surgery to 1.4 +/- 0.5 postoperatively. A significant decrease in the peak PG was observed postoperatively compared to preoperative data (p < 0.01); mean values at two weeks, and at one and two years after surgery were 35 +/- 12, 35 +/- 10, and 33 +/- 10 mmHg, respectively. A significant decrease in the mean LVMI was also noted postoperatively (p < 0.01); mean values at two weeks, and at one and two years after surgery were 134 +/- 35, 110 +/- 17, and 114 +/- 22 g/m2, respectively. The mean effective orifice area index was 0.79 +/- 0.2 cm2/m2. During the mean follow up period of 56 +/- 23 months, all patients received oral anticoagulation with warfarin, and there were no cases of bleeding or thomboembolic complications. Conclusion: Satisfactory early and mid-term outcomes were noted following AVR with the 16 mm ATS AP valve in high-risk elderly patients with a small aortic annulus.
Research Article
Open Access
Biomechanical perspective on the porcine pulmonary root prior to Ross remodeling
Pages 682 - 690
Background and aim of the study: Pulmonary autograft dilation can lead to aortic insufficiency requiring reoperation. Remodeling occurs when the pulmonary root is subjected to systemic pressure. It is unknown whether a regional variability of the material properties exists within the root, resulting in unequally distributed wall stress prior to remodeling after the Ross procedure. The study aim was to determine differences in regional pulmonary root material properties, and to identify changes in wall stress at both pulmonary and systemic pressure. Methods: Five regions of the porcine pulmonary root--anterior and posterior artery, and each sinus--were subjected to displacement-controlled equibiaxial stretch testing. The stress-strain data recorded were used to determine stiffness at 35% strain. Separate finite element simulations of the root were performed using each of the five regional material properties. Tissue dilation and wall stress were compared at pulmonic and systemic pressures. Results: The pulmonary artery (PA) demonstrated tissue anisotropy, and was stiffer in the circumferential than the longitudinal direction (p < 0.001), whereas the sinuses demonstrated no differences in stiffness between the circumferential and longitudinal directions (p = 0.73). Overall, the PA was significantly more compliant than the sinuses, both circumferentially (p = 0.04) and longitudinally (p = 0.007). However, no regional differences in stiffness were found between the anterior and posterior PA (circumferential, p = 0.37; longitudinal, p = 0.06), or among the sinuses (circumferential, p = 0.22; longitudinal, p = 0.38) at 35% strain. Based on finite element simulations, the PA dilated from 35.14 +/- 1.67 cm to 45.98 +/- 2.56 cm, and the sinuses from 35.05 +/- 1.39 cm to 40.02 +/- 2.17 cm from pulmonic to systemic pressure. The maximum wall stress increased from 41.07 +/- 4.17 to 287.06 +/- 31.84 kPa in the PA, and from 55.87 +/- 4.38 to 295.64 +/- 32.97 kPa in the sinuses. Conclusion: Significant inherent differences in compliance were demonstrated between the PA and pulmonary sinuses. These results suggest that the artery dilates more than the sinuses, but is subjected to equally large wall stresses when the systemic pressure is applied prior to remodeling.
Research Article
Open Access
Anti-HLA antibodies and pulmonary valve allograft function after the Ross procedure
Pages 673 - 681
Background and aim of the study: Rejection is a plausible cause of failure of allograft valves, but has not been demonstrated unequivocally in humans. A cross-sectional study has been conducted on the frequency of anti-human leukocyte antigen (HLA) antibodies in order to identify any correlation with allograft function in adult patients, following the Ross procedure. Methods: Anti-HLA antibodies were determined during regular follow up (median 1.1 years postoperatively) in a random sample of 197 patients (151 males, 46 females; mean age 46 +/- 13 years). Panel-reactive antibodies (PRA) were determined by cytotoxicity testing; anti-HLA class 2 antibodies (HLA2AB) were determined by ELISA in a subgroup of 94 patients. Echocardiographic examinations were performed during the first visit and at a median of 6.8 years postoperatively. Results: The prevalence of positive antibody tests was 47% for PRA and 52% for HLA2AB. A slight deterioration of allograft valve function occurred between the two examinations (median maximal pressure gradient increased from 9 mmHg to 13 mmHg, p < 0.001; median degree of regurgitation increased from zero to trivial, p = 0.020). The degree of regurgitation was slightly, but significantly, higher in PRA-positive patients at both examinations (p = 0.008 and p = 0.038). No relationship was observed between PRA status and pressure gradients, nor between HLA2AB status and allograft valve function. Neither were any other risk factors for allograft valve deterioration identified. Conclusion: Subtle, clinically irrelevant and temporally stable differences with regard to regurgitation across the allograft were observed between PRA-positive and -negative patients. These findings neither proved nor disproved rejection, but rather suggested that a slow deterioration of allograft valve function was complex, and most likely multifactorial.
Research Article
Open Access
How important is the anti-Gal antibody response following the implantation of a porcine bioprosthesis?
Pages 671 - 672
Research Article
Open Access
Evaluation of aortic root and valve calcifications by multi-detector computed tomography
Pages 662 - 670
Background and aim of the study: In percutaneous aortic valve replacement (AVR), whilst calcifications are used as landmarks in fluoroscopic placement of the stent, they may also complicate stent placement. In response to this problem, the study aim was to examine severe aortic root calcification by using multi-detector computed tomography (MDCT), to better understand the pathology complicating percutaneous valve placement.
Methods: In 33 patients with severe aortic stenosis and scheduled for surgery, the 'inner orifice' and 'outer fibrous' annulus diameter and area (with and without calcification) were measured, in addition to the distances of the calcifications and coronary ostia from the annulus, using by ECG-gated 64-slice MDCT. Aortic root calcification was evaluated as minimal (< 25% of total circumference), mild (25-50%), moderate (50-75%), and severe (75-100%). Results: The inner orifice annulus area was 5.9 +/- 1.9 cm2 (range: 1.4-10.1 cm2), while the outer fibrous area was 7.5 +/- 1.8 cm2 (range: 4.7-11.5 cm2). The proximal-to-distal extent of valve calcification from the annulus in the mid-center of leaflets was 0.8 +/- 0.26 cm. In 36% of patients, valvular calcification extended +/- 3 mm within the coronary-ostium level. The distance of the coronary ostia from the annulus was variable, with a mean of 1.3 +/- 0.35 cm (range: 0.6-2.4 cm) for the left coronary artery. In 42% of patients, a 'low coronary ostium' (< or = 1.1 cm), and in 6% a 'critical-low-coronary ostium' (< or = 8 mm) was identified. Annulus calcification was present in 100% of cases, but the severity varied widely (severe 50%, moderate 35%, mild 15%). In 36% of cases, the aortic annulus calcification extended caudally into the membranous part of the interventricular septum (and thus into the left ventricular outflow tract), and in 42% of cases (n = 14) into the anterior mitral valve leaflet. Conclusion: The present results indicated that cardiac MDCT may qualify as a primary pre-procedural imaging modality to select patients for percutaneous AVR, based on the measurement and characterization of the aortic root and valve calcification. In comparison to echocardiography, CT will reduce--if not eliminate--difficulties in visualizing the aortic orifice area in heavily calcified valves. Furthermore, knowledge of the exact location of calcific deposits provides a distinct advantage to the fluroscopist for precise placement of the percutaneous aortic valve. Likewise, knowledge of the coronary arteries orifice in relation to the valve plane is critical to prevent inadvertent coronary artery occlusion, and would clearly be beneficial when planning future valve designs.
Research Article
Open Access
P38 MAP kinase in valve interstitial cells is activated by angiotensin II or nitric oxide/peroxynitrite, but reduced by Toll-like receptor-2 stimulation
Pages 653 - 661
Background and aim of the study: The involvement of p38 MAPK in mediating factors that may produce aortic valve disease is unknown. Angiotensin II (Ang II) has been implicated in the development of aortic stenosis through either the generation of free radicals and/or the modulation of inflammatory responses. A variety of proinflammatory factors utilize Toll-like receptors, and these may also play a role in the development of aortic valve disease. Methods: Valve interstitial cells (VICs) were cultured from porcine aortic valves. Cells were treated with Ang II, 3-morpholinosydnonimine (SIN-1), which liberates NO and superoxide anion generating peroxynitrite, or the lipopetide Toll-like receptor-2 (TLR-2) agonist Pam3CSK4. Results: In response to Ang II (1 microM), MAPK phosphorylation levels were increased by 3.5-fold after 15 min, peaked at 4.6-fold after 60 min, and decreased to 1.9-fold greater than control after 120 min of treatment. In response to SIN-1, phosphorylation levels were increased progressively throughout the 90 min of treatment and were significantly (p < 0.05) twofold (1.9 +/- 0.3) greater than control or native p38 MAPK (2.3 +/- 0.4) after 90 min. SB202190, a relatively selective inhibitor of the p38a MAPK isoform, reduced SIN-1-induced p38 MAPK phosphorylation. In contrast, there was a rapid and marked decline in phosphorylated p38 MAPK, in response to Pam3CSK4 that was evident at 30 min; after 90 min, the p38 MAPK level was 85% lower than baseline. Conclusion: p38 MAPK is present in VICs, and is activated by Ang II. Peroxynitrite similarly increased p38 MAPK phosphorylation, which suggests that these two factors involve similar pathways in their effect on VICs. Alternatively, peroxynitrite may be involved in the pathway by which Ang II activates p38 MAPK. The dramatic reduction in p38 MAPK phosphorylation by TLR-2 stimulation excludes a role for this receptor type in mediating Ang II or peroxynitrite effects, and suggests that inflammatory factors that act through TLR-2 to dephosphorylate p38 MAPK utilize pathways different from Ang II or peroxynitrite, to produce their effect on the aortic valve.
Research Article
Open Access
Apelin and its receptor APJ in human aortic valve stenosis
Pages 644 - 652
Background and aim of the study: Aortic valve stenosis (AS) is an actively regulated pathobiological process that shows some hallmarks of atherosclerosis. Apelin and its receptor, APJ, are highly expressed in the heart, and the proposed effects of the apelin-APJ system are opposite to those of the angiotensin II-AT1-receptor pathway. The role of the apelin-APJ signaling pathway in calcified aortic valve disease is unknown. Methods: The study involved the characterization and comparison of expression of apelin and APJ as well as angiotensin II receptors (AT1 and AT2) in the aortic valves of patients with normal valves (n = 6), aortic regurgitation (n = 9 AR), regurgitation and fibrosis/mild sclerosis (n = 14), and AS (n = 25). Results: By employing the reverse-transcriptase polymerase chain reaction (RT-PCR), the gene expression of apelin (3.63-fold, p = 0.001) and the APJ receptor (2.70-fold, p = 0.01) were shown to be significantly up-regulated in stenotic valves when compared to controls. In addition, APJ receptor mRNA levels were higher (2.9-fold, p = 0.010) in the AR + sclerosis group when compared to controls. Using immunohistochemistry, apelin was shown to be localized in stenotic aortic valves to the valvular endothelial layer of the aortic valve, to vascular endothelial cells in neovessels, and to fibroblasts and macrophages adjacent to vessels in the stromal area. AT2-receptor mRNA levels were 90% (p < 0.001) lower in stenotic valves. In contrast, the gene expression of AT1-receptors did not differ significantly among the groups. Conclusion: Aortic valve stenosis is characterized by an up-regulation of the apelin-APJ signaling pathway, revealing a possible novel target for drug discovery in calcified aortic valve disease by suppressing chemotaxis, angiogenesis and osteoblast activity, all of which are well-documented phenomena in the disease process.
Research Article
Open Access
Evaluation of aortic valve stenosis by cardiac multislice computed tomography compared with echocardiography: a systematic review and meta-analysis
Pages 634 - 643
Background and aim of the study: It has not yet been established whether multi-slice computed tomography (MSCT) is reliable for the quantification of aortic valve area (AVA) in patients with aortic valve stenosis (AVS) and simultaneously for assessment of the coronary anatomy. The study aim, via a systematic literature review and meta-analysis, was to explore whether MSCT is a reliable method for AVA quantification, and simultaneously to assess the coronary anatomy in patients with AVS. Methods: A comprehensive systematic literature search and meta-analysis was conducted that included 14 studies totaling 470 patients. The meta-analysis was carried out to examine the reliability of MSCT compared to transthoracic echocardiography (TTE) and transesophageal echocardiography (TEE). Seven studies including 266 patients with AVS were also eligible for a secondary analysis to compare the accuracy of MSCT with invasive coronary angiography. Results: The AVA was measured by MSCT and TTE in all 14 studies, and by TEE in four studies. The results of the meta-analyses showed that planimetry by MSCT overestimated the AVA, with a bias of 0.08 (95% CI 0.04, 0.13) cm2) (p = 0.0001) compared to TTE. The MSCT measurement was concordant with planimetry by TEE, with a small bias of -0.02 (95% CI -0.16, 0.11) cm2 (p = 0.71). MSCT, when compared to invasive angiography for the detection of significant coronary stenosis, showed sensitivity, specificity and diagnostic odds ratio of 95.5% (95% CI 88-99), 81% (95% CI 75-86)%, and 53 (95% CI 19-147), respectively. Conclusion: MSCT is a reliable method for the quantification of AVA, and represents a promising technique for the combined evaluation of aortic valve morphology and coronary artery disease.
Research Article
Open Access
Association between mitral and aortic valve calcification and preferential left or right coronary artery disease
Pages 627 - 633
Background and aim of the study: Mitral annular calcification (MAC) and aortic valve calcification (AVC) are predictive of coronary artery disease (CAD). However, no data exist concerning the association between preferential CAD side localization to the left or right coronary arteries and MAC or AVC. Methods: A cohort analysis was performed of 1,000 consecutive coronary angiographies recorded in patients with CAD. The angiographies were divided according to the distribution of CAD to the isolated right coronary tree disease, left coronary tree disease, or both. The echocardiograms were reviewed for MAC, AVC or combined valvular calcification (CVC). Results: Significant CAD (lumenal stenosis > 70%) was observed in 688 patients, among whom 167 had isolated (right or left) CAD and 521 double-sided coronary tree disease. Valvular calcification (VC) was observed in 70 (42%) of the isolated CAD patients; of these, 41 had isolated left CAD and 29 isolated right CAD. Among the isolated left CAD patients with VC, 13 (32%) had AVC, 22 (53%) had CVC, and only six (15%) had MAC (p < 0.01). Among the isolated right CAD patients with VC, 18 (62%) had MAC, nine (31%) had CVC, and only two (7%) had AVC (p < 0.01). VC was observed in 266 patients (51%) with mixed CAD; of these, 152 (57%) had CVC, 103 (39%) had AVC, and 11 (4%) had MAC (p < 0.01). Conclusion: Isolated left CAD is associated with AVC or CVC more frequently than with MAC. In contrast, isolated right CAD is associated with MAC or CVC, but rarely with AVC.
Research Article
Open Access
Initial experience with dual antiplatelet thromboprophylaxis using clopidogrel and aspirin in patients with mechanical aortic prostheses
Pages 617 - 626
Background and aim of the study: The aortic mechanical prosthesis (AMP) generates shear stress and causes erythrocyte fragmentation with ADP release that leads to platelet activation, the cause of thromboembolism. Thromboprophylaxis with the antiplatelet agents clopidogrel and aspirin (Clop-ASA) should reduce thromboembolic events in patients receiving an AMP. Methods: Over an eight-year period at the authors' institutions, a total of 135 patients underwent aortic valve replacement (AVR), with or without concomitant thoracic aortic procedures, and received Clop-ASA as thromboprophylaxis. Platelet reactivity was measured using the Verify Now system. Thromboelastography was commenced in August 2006, and patients were followed at six-month intervals, with echocardiography and assessment of platelet reactivity. Results: The total follow up was 4,776 months (equivalent to 398 patient-years (pt-yr)); the average follow up was 35.4 +/- 25 months. During follow up, 18 patients (13.3%) died, eight from coronary artery disease and three from valve-related causes. Five patients (3.7%; 1.2%/pt-yr) had bleeding complications, but none experienced valve thrombosis. Two patients (1.5%; 0.5%/pt-yr) had a transient ischemic attack (TIA); one of these occurred in a patient who discontinued Clop-ASA, and the other in a responder to Clop-ASA. Seven patients (5.2%; 1.7%/pt-yr) had strokes, one of which occurred at 48.5 months after AVR. Of the remaining six patients who had a stroke, one was a non-responder to clopidogrel and five had stopped taking Clop-ASA. The incidence of strokes before using the Accumetrics and TEG devices was 2.5% per pt-yr, but only 1.0% per pt-yr thereafter. Conclusion: Thromboprophylaxis in patients with AMP receiving Clop-ASA seems to be effective. Patients had a low incidence of bleeding, TIA and ischemic stroke, and no valve thrombosis. The use of assays to determine platelet reactivity helped to identify those patients who were resistant to clopidogrel, hyporesponders, and poorly compliant patients. Notably, the incidence of strokes after implementing assays to monitor platelet reactivity was reduced. Deaths were due primarily to myocardial infarction, and none of the deaths was anticoagulant-related. Patients receiving Clop-ASA should undergo routine testing of platelet reactivity, and also continue antiplatelet therapy so as to reduce the risk of ischemic stroke.
Research Article
Open Access
Results of atrial fibrillation ablation during mitral surgery in patients with poor electro-anatomical substrate
Pages 607 - 616
Background and aim of the study: Enlarged (> 50 mm) atria, longstanding (> 5 years) persistent atrial fibrillation (AF) and age > 70 years are considered predictive of recurrent AF following surgical ablation. The electrophysiological and clinical outcome after AF-ablation was evaluated in high-risk patients undergoing concomitant procedures. Methods: Between January 2005 and January 2009, a total of 45 patients who complied with the three major predictors of failure, but who had undergone AF ablation ('left + right bipolar radiofrequency Maze') during concomitant mitral surgery were followed up. Freedom from AF, atrial flutter (AFL) and atrial tachycardia (AT), without anti-arrhythmic therapy (discontinued at the sixth month) was the primary endpoint. Survival, freedom from AF/AFL/AT with anti-arrhythmic therapy, early events during post-ablation blanking period, freedom from congestive heart failure (CHF) and from re-hospitalization, and changes in NYHA functional class were registered. Results: Postoperatively, 18 patients (40%) showed sinus rhythm (SR) at admission to the intensive care unit, while 16 (26%) showed junctional rhythm and five (11%) required definitive pacemaker. Eleven of the 40 patients (28%) were discharged without a pacemaker, and experienced early events during the post-ablation blanking period. After a mean of 21 +/- 14 months' follow up, the actuarial survival was 88 +/- 7%. The prevalence of SR at six, 12, and 18 months was 74%, 64%, and 64% respectively. Freedom from AF/AFL/AT was 54 +/- 10% without anti-arrhythmic medications, and 51 +/- 9% with such drugs. Freedom from CHF was 85 +/- 6%, and significantly better in SR patients (94 +/- 6%) than in AF patients (69 +/- 13%; p = 0.018). Freedom from rehospitalization was 75 +/- 8%, and better in SR patients (94 +/- 6%) than in AF patients (37 +/- 14%; p = 0.0001). Accordingly, when compared to AF patients, the NYHA class was significantly ameliorated in SR patients at both six months (1.4 +/- 0.6 versus 2.7 +/- 0.9) and at the final follow up control (1.2 +/- 0.5 versus 1.9 +/- 0.7; p < 0.0001). The E/A wave recovered in 22 (85%) of the SR patients. Conclusion: AF ablation during mitral valve surgery achieves good electrophysiological results, even in patients traditionally considered as poor candidates. SR recovery allows a higher freedom from CHF and rehospitalization, with a better functional recovery when compared to AF.
Research Article
Open Access
Regurgitant flow in ischemic and dilative mitral regurgitation
Pages 598 - 606
Background and aim of the study: It is well established that there are geometric differences between ischemic and dilative mitral regurgitation (MR), yet data on the hemodynamic consequences of these differences are scarce. The study aim was to determine whether mitral regurgitant flows in ischemic MR differ from those in dilative MR. Methods: A left heart simulator was developed to evaluate possible differences in regurgitant flows between two pathological mitral valve configurations, ischemic and dilative. Ischemic MR was simulated by increasing the baseline intercommissural diameter (CC) by 10%, the baseline septolateral (SL) diameter by 30%, and by displacing the posteromedial papillary muscle (PM) to the apical posterolateral position. Dilative MR was simulated by increasing the baseline SL and CC diameters by 30%, and by a symmetrical displacement of both PMs. Mitral regurgitant flow measurements were carried out under transmitral pressures ranging from 40 to 140 mmHg (increments of 15 mmHg). Camera snapshots of the mitral annulus were used to accurately determine mitral annular geometry by measuring the SL and CC diameters. Results: A total of 24 measurements was made on four porcine mitral valves; 14 to evaluate ischemic MR, and 10 to evaluate dilative MR. In ischemic MR, a constant regurgitant flow was observed throughout the pressure range tested. In dilative MR, increasing the transmitral pressure caused the regurgitant flows to decrease exponentially. The mitral annulus snapshot analysis showed that displacement of the posteromedial PM in ischemic MR caused the regurgitation orifice to appear at the tented side of the valve. An additional regurgitation orifice was formed through bulging (prolapse) of the leaflets at the contralateral commissure. The phenomenon was not observed in the dilative mitral valve configuration, where a central regurgitation orifice appeared with symmetrical PM displacement. Conclusion: These data suggest that geometric differences between ischemic and dilative MR translate into significantly different hemodynamic properties of insufficient mitral valves.