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How to cite: Bonow, R. O., Carabello, B., de Leon, A. C., Edmunds, L. H., Jr, Fedderly, B. J., Freed, M. D., Gaasch, W. H., McKay, C. R., Nishimura, R. A., O'Gara, P. T., O'Rourke, R. A., Rahimtoola, S. H., Ritchie, J. L., Cheitlin, M. D., Eagle, K. A., Gardner, T. J., Garson, A., Jr, Gibbons, R. J., Russell, R. O., Ryan, T. J., … Smith, S. C., Jr (1998). ACC/AHA Guidelines for the Management of Patients With Valvular Heart Disease. Executive Summary. A report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee on Management of Patients With Valvular Heart Disease). The Journal of heart valve disease, 7(6), 672–707.

A four-year-old girl presented with an apical mass of the right ventricle, pulmonary embolism and hypereosinophilia, and was shown to be infected with Toxocara canis. Cardiac involvement was represented by endomyocardial fibrosis, mainly at the apex of the right ventricle, mural thrombi and tricuspid regurgitation. Hypereosinophilia appears to be the head point at the basis of multiple organ damage in Löeffler endomyocarditis. The disease mechanism proposed is the eosinophilic production of peroxidases, which are cytotoxic when released in large amounts into the blood flow. Treatment is based on etiologic and corticosteroid therapy (prednisolone 1-2 mg/kg/day); surgical therapy is indicated in the end stages of the pathologic process.

How to cite: De Cock, C., Lemaitre, J., & Deuvaert, F. E. (1998). Löeffler endomyocarditis: a clinical presentation as right ventricular tumor. The Journal of heart valve disease, 7(6), 668–671.

Background and aims of the study: This study compares the cavitation potential of prosthetic heart valves based on valve closing dynamics.

Methods: A laser sweeping technique measured valve closing dynamics (average closing velocity and deceleration) immediately before valve closure. A high-fidelity, piezoelectric pressure transducer was mounted proximal to the mitral valve and measured the high-frequency pressure fluctuations caused by cavitation bubble formation and collapse after valve closure. The band-pass filtered root mean squared (RMS) value of the mitral pressure signal was used as a measure of cavitation intensity. The combination of these two techniques allowed the direct correlation of valve dynamics and cavitation intensity for each valve closure. The effects of three parameters on prosthetic heart valve dynamics and cavitation were examined: valve geometry (Medtronic Hall and Björk-Shiley Monostrut), occluder material (pyrolytic carbon and Delrin), and gap width between the occluder and housing. A dimensional analysis was also performed to investigate the general form of the relationship between valve dynamics and cavitation intensity.

Results: For all of the valves investigated in this study, the RMS pressure increased (signifying an increase in cavitation) as the average closing velocity and deceleration increased. In order to compare the cavitation potential of the valves, the RMS pressure was estimated at specific closing velocities using the linear regression of RMS pressure versus average closing velocity for each valve. The effects of valve geometry, occluder material and gap width were then examined at high valve loading conditions (closing velocity of 4.0 m/s). For both pyrolytic carbon and Delrin, the Medtronic Hall valves had significantly higher RMS pressures than did the Björk-Shiley Monostrut valves. For a given valve geometry, the pyrolytic carbon occluder had a significantly higher RMS pressure than the Delrin occluder. The valve gap width did not have a significant effect on RMS pressure. The dimensional analysis revealed the general relationship among average closing velocity, occluder material properties and cavitation intensity.

Conclusions: The results presented here contribute to our fundamental understanding of cavitation on mechanical heart valves.

How to cite: Zapanta, C. M., Stinebring, D. R., Deutsch, S., Geselowitz, D. B., & Tarbell, J. M. (1998). A comparison of the cavitation potential of prosthetic heart valves based on valve closing dynamics. The Journal of heart valve disease, 7(6), 655–667.

Background and aim of the study: The Ultracor heart valve is a recent entry in the evolution of the tilting disc valve. This report summarizes the experience with the Ultracor valve from three European centers.

Methods: Between 1990 and 1996, 446 patients received 499 Ultracor heart valve prostheses in 450 procedures, including 225 (50.0%) aortic, 172 (38.2%) mitral and 49 (10.9%) double valve replacements. An additional four (1.0%) patients had mitral valve replacement (MVR) added to a previous aortic valve replacement (AVR) and were considered double valve replacement (DVR) patients. The total follow up was 751 patient-years (pt-yr) for AVR (mean 3.4), 440 pt-yr for MVR (mean 2.6) and 125 pt-yr for DVR (mean 2.4). Nine patients (one AVR, eight MVR) were lost to follow up, which was 98% complete.

Results: The actuarial survival rate, including operative mortality rate, at five years was 90% for AVR, 77% for MVR and 82% for DVR. The linearized complication rates (%/year) for AVR, MVR and DVR were: 2.1, 4.0 and 4.0 for late mortality; 0.1, 3.0 and 0.8 for thromboembolism; 0, 0.2 and 0 for thrombosis; 2.0, 1.6 and 1.6 for anticoagulant-related hemorrhage (ACH); 0.3, 0.5 and 1.6 for prosthetic valve endocarditis (PVE); and 0.5, 0.9 and 3.2 for reoperation, respectively. The actuarial rates of freedom from complications at five years were: thromboembolism, 99% for AVR and 88% for MVR; thrombosis, 100% for AVR and 99% for MVR; ACH, 91% for AVR and 94% for MVR; PVE, 99% for AVR and 97% for MVR; reoperation, 98% for AVR and 98% for MVR. No structural failure was observed.

Conclusions: Seven years' experience showed the Ultracor heart valve prosthesis to be comparable with other currently used mechanical heart valves. Continued evaluation of this prosthesis is warranted in order to obtain a more extended clinical follow up.

How to cite: Li, H. H., Jeffrey, R. R., Davidson, K. G., Seifert, D., Körfer, R., & Grunkemeier, G. L. (1998). The Ultracor tilting disc heart valve prosthesis: a seven-year study. The Journal of heart valve disease, 7(6), 647–654.

Background and aims of the study: Antimicrobial coating of medical devices has recently emerged as a potentially effective method for preventing device-related infections. The objective of this animal study was to examine in vivo the antimicrobial efficacy of prosthetic heart valve sewing ring fabric coated with: (i) silver; (ii) combined minocycline and rifampin (M/R); or (iii) combined chlorhexidine and chloroxylenol (CH/CX).

Methods: A rabbit model of Staphylococcus aureus colonization and infection of subcutaneously implanted fabric of prosthetic heart valve sewing rings was used. Following administration of anesthesia and preoperative antibiotic prophylaxis, 0.5 x 0.5 cm samples of fabric were placed subcutaneously into the back of rabbits. Each rabbit received a total of eight samples: (i) two uncoated; (ii) two silver-coated; (iii) two M/R-coated; and (iv) two CH/CX-coated. After injecting a bacterial inoculum of 2 x 10(5) c.f.u. of S. aureus onto each implanted sample, the wounds were sutured. Rabbits were monitored daily for one week, killed and the test fabrics removed and cultured.

Results: Rates of device colonization, device-related infection and device-related abscess were similar between the uncoated and silver-coated devices. Devices coated with M/R were less likely to be colonized or cause device-related infection when compared with uncoated devices, and less likely to be associated with abscess formation than silver-coated devices. There was a tendency for CH/CX-coated devices to be less colonized than uncoated devices. Only M/R-coated and CH/CX-coated devices produced zones of inhibition in vitro. Implantation of M/R-coated and CH/CX-coated devices in rabbits did not result in detectable systemic concentrations of the antimicrobial coating agents. Colonization of antimicrobial-coated devices was not associated with resistant S. aureus isolates.

Conclusions: These results suggest that silver-coated sewing rings may not prove to be clinically anti-infective. In contrast, antimicrobial-coated sewing rings that produce effective zones of inhibition, particularly those coated with M/R, are likely to be clinically protective.

How to cite: Darouiche, R. O., Meade, R., Mansouri, M., & Raad, I. I. (1998). In vivo efficacy of antimicrobial-coated fabric from prosthetic heart valve sewing rings. The Journal of heart valve disease, 7(6), 639–646.

Background and aim of the study: The St. Jude Medical (SJM) Epic valve has been designed to diminish the risk of prosthetic valve endocarditis by the use of silver-coated polyester fabric, and to inhibit dystrophic calcification by the use of ethanol pretreatment.

Methods: A 20-week juvenile sheep mitral valve implant model was used to determine safety and efficacy of the device, as well as the rate of silver release and degree of dystrophic calcification. The SJM Epic valves were compared with SJM Biocor porcine valves (not ethanol-pretreated, not silver-modified polyester fabric) and Baxter Carpentier-EdwardsR standard valves.

Results: Blood concentrations of silver reached a maximum of 40 p.p.b. within 10 days of SJM Epic valve implantation, and were well below toxic levels (300 p.p.b.). Blood silver concentrations returned to baseline within 30 days after surgery. Maximal silver accumulation occurred in the liver (16.75 mg/g dry weight); concentrations in the brain, spleen, kidney and lung were similar to those reported for other silver-modified prosthetic valves. No statistically significant difference was found in calcium content between SJM Epic and Biocor valves. The fibrous response to the sewing cuff was similar among the three valve types.

Conclusions: At all times tested, silver release from the SJM Epic valve led to blood concentrations well below toxic levels. Although calcification in the two SJM valve groups was extremely low, the 20-week sheep model may be insufficiently sensitive to detect differences in calcium accumulation in modern bioprosthetic valves.

How to cite: Langanki, D., Ogle, M. F., Cameron, J. D., Lirtzman, R. A., Schroeder, R. F., & Mirsch, M. W. (1998). Evaluation of a novel bioprosthetic heart valve incorporating anticalcification and antimicrobial technology in a sheep model. The Journal of heart valve disease, 7(6), 633–638.

Background and aim of the study: Historically, the pyrolytic carbon used in mechanical prosthetic heart valves contained small amounts of silicon, this being a necessary additive to achieve consistently the hardness required for wear resistance. New processing technology has allowed the deposition of pyrolytic carbon without silicon, while maintaining adequate hardness to ensure wear resistance.

Methods: A parametric study of coating parameters identified the conditions necessary to produce the optimal pure carbon material.

Results: In comparison with silicon-alloyed carbon, the pure carbon was found to be about 20% stronger, have a strain-to-failure about 25% higher and have a greater toughness.

Conclusions: The enhanced strength, deformability and toughness of the new carbon permits designers to utilize component shapes and dimensions that could not be manufactured using the silicon-alloyed carbons. Such design features have hemodynamic benefits resulting in valve performance improvements.

How to cite: Ely, J. L., Emken, M. R., Accuntius, J. A., Wilde, D. S., Haubold, A. D., More, R. B., & Bokros, J. C. (1998). Pure pyrolytic carbon: preparation and properties of a new material, On-X carbon for mechanical heart valve prostheses. The Journal of heart valve disease, 7(6), 626–632.

Background and aim of the study: In a number of corrective and palliative procedures the autologous pulmonary valve is used as the systemic semilunar valve. This study reviews the surgical results and function of the native pulmonary valve in the systemic position after various surgical procedures.

Methods: Between January 1994 and December 1997, the autologous pulmonary valve was transferred functionally or anatomically into the systemic circulation in 89 patients. Follow up echocardiograms and cardiac angiograms were reviewed for 51 neonates with transposition of the great arteries after an arterial switch operation (ASO), in 21 patients after first-stage palliation of hypoplastic left heart syndrome (HLHS), in eight children and adults with pulmonary autograft aortic valve replacement (Ross procedure), and in nine patients with a pulmonary artery-to-aortic anastomosis (Damus-Kaye-Stansel (DKS) procedure) in complex heart defects with outflow obstruction.

Results: Nine patients (five with HLHS) died; thus, overall mortality rate was 10.2%. There was no evidence of valve-related mortality. Trivial insufficiency following ASO was noted in 11 patients, with no progression of incompetence over time. None of the HLHS patients had pulmonary insufficiency preoperatively, but all showed mild regurgitation on postoperative echocardiography. There was a moderate increase in insufficiency which was attenuated after an early second-stage palliation. Three of nine patients undergoing a DKS anastomosis demonstrated a hemodynamically insignificant insufficiency. Modification of the surgical technique avoided postoperative regurgitation. Four of seven patients having a Ross procedure showed trivial but non-progressive neoaortic regurgitation.

Conclusions: Based on this experience, the autologous pulmonary valve performs adequately at intermediate term follow up. Postoperatively, trivial regurgitation was a frequent finding but was hemodynamically insignificant. Progression or late development of insufficiency as well as stenosis were rare problems.

How to cite: Schmid, F. X., Hilker, M., Kampmann, C., Mayer, E., & Oelert, H. (1998). Clinical performance of the native pulmonary valve in the systemic circulation. The Journal of heart valve disease, 7(6), 620–625.

Background and aims of the study: Aortic valve disease in the pediatric population poses special problems to surgeons and cardiologists. The pulmonary autograft has proven to be a good alternative for aortic valve replacement and left ventricular outflow tract (LVOT) reconstruction in this special group.

Methods: Forty-one children (mean age 10.0 +/- 4.8 (SD) years; range: 35 days to 18.8 years) underwent aortic root replacement with a pulmonary autograft between February 1994 and April 1998. Twenty-one patients (51%) had previous cardiac surgery; seven (17%) had balloon valvulotomy. Aortic root replacement was combined with other techniques for various disorders, including tunnel LVOT obstruction, ventricular septal defect (VSD)-aortic insufficiency complex, neoaortic insufficiency following arterial switch procedure, and subvalvular stenosis following correction of type B interruption of the aortic arch (IAA) with VSD (IAA-B/VSD).

Results: The mean follow up was 1.7 +/- 1.0 years (range 44 days to 4.1 years). Total follow up time was 67.8 patient-years. Two patients, both after repair of interrupted aortic arch, died intraoperatively (4.9%). There was no late mortality. Two patients were reoperated on (5.1%), one for autograft insufficiency due to cuspal perforation and one for right ventricular outflow tract stenosis at the distal anastomosis. Thirty-eight patients (97%) are currently in NYHA class I; one child with a preoperatively poor left ventricular function did not improve and is in class II. At the latest echocardiographic follow up, neoaortic regurgitation was absent in 19% of patients, trivial in 69% and mild in 11%. Homograft insufficiency was absent in 64%, trivial in 31% and mild in 6%. All mean gradients for both autograft and homograft were < 15 mmHg.

Conclusions: The Ross operation can be performed with good results in infants and children with different forms of LVOT obstruction and aortic insufficiency, though aortic stenosis following IAA-B/VSD repair poses a surgically difficult problem.

How to cite: Braun, J., Hazekamp, M. G., Schoof, P. H., Ottenkamp, J., & Huysmans, H. A. (1998). Short-term follow up of the Ross operation in children. The Journal of heart valve disease, 7(6), 615–619.

Background and aims of the study: This study investigated the efficacy of postoperative ticlopidine as antiplatelet therapy in patients shortly after heart valve repair or replacement.

Methods: Between 1990 and 1995, 235 consecutive patients underwent either valve repair (n = 67) or replacement with a bioprosthesis (n = 168). The bioprostheses used were Carpentier-Edwards porcine or pericardial (n = 158) valves, Prima stentless valves (n = 3) and cryopreserved homografts (n = 7). Types of repair were aortic (one), mitral annuloplasty with Carpentier ring (65) and tricuspid repair (one). Mean patient age was 67 (range: 16 to 83) years for valve replacement and 57 (range: 32 to 74) years for repair (p < 0.01). Atrial fibrillation occurred in 34% of patients. The hospital mortality rate was 11% (26 patients). Of the 209 survivors, 137 were assigned to antiplatelet treatment with ticlopidine for the first three months of follow up. The other 72 received either oral anticoagulation (coumadin; n = 40), aspirin (n = 14) or no medication (n = 18). In 15 patients, ticlopidine treatment was interrupted due to diarrhea (13 cases), mild allergic reaction (one) or anemia (one). The mean follow up was 3.2 years (range: 1 month to 6 years); cumulative follow up was 684 patient-years (pt-yr) and was complete in 96% of cases.

Results: There were two episodes of thromboembolism in the ticlopidine group at 1 month and 6 months respectively, with a linearized incidence of 0.5% pt-yr. In the coumadin group there were four episodes of thromboembolism, three within the first three months of follow up. The linearized incidence was 3% pt-yr (p < 0.01). There were three episodes of hemorrhage in the ticlopidine group in the first three months of follow up and one in the coumadin group. The linearized incidence was 0.75% pt-yr.

Conclusions: Following heart valve repair or replacement with a bioprosthesis, the first three months is a high-risk period for thromboembolism. Ticlopidine seems to prevent this complication better than conventional therapy with oral anticoagulants. Nevertheless, hemorrhage continues to be a problem with ticlopidine therapy.

How to cite: Aramendi, J. L., Agredo, J., Llorente, A., Larrarte, C., & Pijoan, J. (1998). Prevention of thromboembolism with ticlopidine shortly after valve repair or replacement with a bioprosthesis. The Journal of heart valve disease, 7(6), 610–614.

Background and aims of the study: Thrombosis is one of the most feared and life-threatening complications of mechanical heart valves (MHV), with an incidence of 1-3 per 100 patient-years. Hypercoagulable states are highly prevalent in the general population and can predispose MHV to thrombus formation. Thus, we conducted a study to investigate the frequency of hypercoagulable states in patients with MHV who had recurrent thrombosis at least twice after valve implantation.

Methods: Fifteen patients (mean age 42 +/- 11 years; range: 18 to 55 years) with recurrent thrombosis of MHV (2.4 +/- 0.8 recurrences/patient) (group 1) and 15 matched patients (mean age 40 +/- 12 years; range: 18 to 55 years) with MHV without thrombosis (group 2) were followed up with transthoracic and transesophageal echocardiography. Patients' sera were monitored for antibodies to cardiolipin (ACLA-IgG and ACLA-IgM), phosphatidylserine (APSA), lupus-type anticoagulant (LA) and lipoprotein(a) (LP(a)).

Results: Average values for group 1 versus group 2 were: ACLA-IgG (normal range < 15 GPLU/ml) 24.7 +/- 14.6 versus 6.2 +/- 2.7 (p < 0.001); ACLA-IgM (< 12.5 MPLU/ml) 7.9 +/- 5.0 versus 3.3 +/- 1.7 (u = 185; p < 0.001); APSA (< 12 RLU/ml) 4.8 +/- 5.7 and 2.9 +/- 1.2 (p = 0.56); and LP(a) (< 30 mg/dl) 36.5 +/- 26.5 and 13.4 +/- 7.1 (p < 0.001). The frequency of LA-positive cases was 4/15 in group 1 and 0/15 in group 2 (p > 0.05). The frequency of abnormally high levels of ACLA-IgG was 9/15 in group 1 and 0/15 in group 2 (p < 0.001); of ACLA-IgM, 2/15 in group 1 and 0/15 in group 2 (p > 0.05); of APSA, 1/15 in group 1 and 0/15 in group 2 (p > 0.05); and of LP(a), 5/15 in group 1 and 0/15 in group 2 (p < 0.05). At least one of the factors included in this study was abnormal in 14 of 15 (93%) patients (p < 0.0001).

Conclusions: Hypercoagulable states are highly prevalent in patients with recurrent thrombosis of MHV. All patients evaluated for therapy of obstructive thrombosis of MHV should be investigated for hypercoagulable state. Moreover, in high-risk patients, surgical replacement of the MHV with a bioprosthesis should be considered.

How to cite: Gencbay, M., Turan, F., Degertekin, M., Eksi, N., Mutlu, B., & Unalp, A. (1998). High prevalence of hypercoagulable states in patients with recurrent thrombosis of mechanical heart valves. The Journal of heart valve disease, 7(6), 601–609.

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How to cite: Horstkotte, D., & Riess, H. (1998). Thromboembolic complications following heart valve replacement: the role of patient-related coagulability. The Journal of heart valve disease, 7(6), 598–600.