A 41-year-old man being treated with methotrexate for psoriasis underwent aortic valve replacement. He subsequently developed fulminating bacterial endocarditis. Bacterial endocarditis occurs in 1-2% of cases after prosthetic valve replacement and has a high mortality. The long-term use of methotrexate and similar drugs is increasing in conditions such as psoriasis, rheumatoid arthritis and inflammatory bowel disease. Thus, more patients undergoing heart valve surgery will be taking these preparations for coexisting disease. As methotrexate increases the risk of infection, its perioperative use in these patients requires further evaluation.

How to cite: Wilkinson N. M. (1999). Fatal bacterial endocarditis following aortic valve replacement in a patient being treated with methotrexate. The Journal of heart valve disease, 8(5), 591–592.

Materials for implanted heart valves face challenges unmatched for most mechanical applications. The valves must function without interruption for lifetimes in the order of 10(9) cycles in a corrosive, hostile environment. A particular carbon has been widely used for the past three decades. The mechanical behavior of this isotropic pyrolytic carbon (PyC), with and without silicon alloying, was studied in this research program. Several questions were addressed: the fatigue strength at lifetimes of 10(9) cycles, the threshold for crack growth, the validity of fracture mechanics for PyC, and the statistics of ultra-high survival under cyclic stress. It was found that cyclic stressing within the scatter band of the static strength did not initiate cracks. Furthermore, artificially induced cracks did not grow under cyclic stressing below a threshold stress intensity factor. This threshold stress intensity factor was valid over a wide range of crack lengths. No failures occurred when batches of 29 specimens were tested above the service stress at 6 x 10(8) cycles. Cyclic stressing did not reduce the static strength. The service stress is a small fraction of the fracture strength; thus, a very high probability of survival can be ensured by a proof test of the assembly.

How to cite: Ma, L., & Sines, G. H. (1999). Unalloyed pyrolytic carbon for implanted mechanical heart valves. The Journal of heart valve disease, 8(5), 578–585.

Background and aim of the study: In the past, valve homografts have been used in the treatment of aortic endocarditis. This report details our experience in tricuspid valve replacement using cryopreserved mitral homografts in HIV-positive drug addicts with infective endocarditis.

Methods: Five HIV-1-infected drug addicts with active uncontrollable tricuspid valve endocarditis underwent tricuspid valve replacement with a cryopreserved mitral homograft.

Results: There was no early mortality, and median follow up was 5 years (range: 1 to 6 years). One late mortality occurred as a result of heroin overdose. Three of the five patients developed six episodes of recurrent bacterial tricuspid endocarditis on the homograft; these were cured successfully with antibiotics. All survivors remain in NYHA functional class I. The latest transthoracic echocardiography examination showed mild, moderate or severe regurgitation in one, two and two patients, respectively. To date, neither homograft calcification nor rupture of the papillary muscle has been detected.

Conclusions: This novel technique is considered to be an adequate approach to these cases of uncontrollable infectious disease. Further episodes of valvular infection can be managed medically.

How to cite: Mestres, C. A., Miro, J. M., Pare, J. C., & Pomar, J. L. (1999). Six-year experience with cryopreserved mitral homografts in the treatment of tricuspid valve endocarditis in HIV-infected drug addicts. The Journal of heart valve disease, 8(5), 575–577.

Background and aims of the study: Patients with symptoms of right heart failure due to severe tricuspid regurgitation following a prior operation on left heart valves present a difficult problem. The outcome of tricuspid surgery in this setting is not well defined. We describe a single-center experience of isolated tricuspid valve surgery after prior left heart valve surgery, and analyze potential risk factors for a poor outcome.

Methods: Thirty-four patients who underwent isolated tricuspid valve operation for severe tricuspid regurgitation following prior valvular surgery for left-sided valve disease between 1980 and 1997 were identified. Charts were reviewed for clinical, echocardiographic, catheterization and surgical data. Follow up of survivors was conducted by telephone to ascertain functional status.

Results: Three patients died in hospital (early mortality rate, 8.8%). At a follow up of 71 +/- 39 months, 13 patients were alive and 21 reached an end-point (three cardiac reoperations, 18 deaths). Event-free actuarial survival at five years was 41.6 +/- 9.2%. Patients who were alive at follow up had a mean NYHA functional class of 2.1 +/- 0.6 compared with 3.4 +/- 0.5 preoperatively; 85% of survivors were symptomatically improved. Predictors of poor outcome were: increased age at the time of tricuspid surgery (p = 0.0007) and higher number of prior cardiac operations (one versus two or three, p-value 0.01, relative risk 3.4). Pulmonary artery systolic pressure, left ventricular ejection fraction, right ventricular function and size, annulus diameter, tricuspid valve pathology, and valve replacement versus repair were not predictive of outcome.

Conclusions: Isolated tricuspid valve surgery for severe tricuspid regurgitation following prior surgery for left-sided heart valve disease can be performed with acceptable early mortality. There remains a high late mortality that is predicted only by age and the number of previous cardiac operations. However, in this selected group of severely symptomatic patients, significant improvement in symptoms are achieved in the survivors.

How to cite: Staab, M. E., Nishimura, R. A., & Dearani, J. A. (1999). Isolated tricuspid valve surgery for severe tricuspid regurgitation following prior left heart valve surgery: analysis of outcome in 34 patients. The Journal of heart valve disease, 8(5), 567–574.

A 61-year-old man was admitted with acute posterior myocardial infarction and, on physical examination, was shown to have a mitral regurgitation (MR) murmur. Transthoracic echocardiography (TTE) showed severe hypokinesis of the posterior wall and severe MR by color flow. Right heart catheterization with a balloon-tipped catheter revealed a pulmonary artery wedge pressure of 30 mmHg. No 'step-up' was seen in blood samples from the right atrium and right ventricle. On angiography, a subtotal occlusion of the mid circumflex artery was found which was angioplastied and stented. As the patient's clinical condition did not improve, he underwent transesophageal echocardiography (TEE) for further evaluation. This showed complete rupture of the posteromedial papillary muscle. The patient underwent urgent surgery with successful mitral valve replacement. The postoperative course was uncomplicated, and clinical improvement seen. This case report underscores the value of TEE in accurate preoperative diagnosis of papillary muscle rupture by providing preoperative anatomic details of the mitral valve apparatus and surrounding structures.

How to cite: Assi, E. R., & Tak, T. (1999). Posterior myocardial infarction complicated by rupture of the posteromedial papillary muscle. The Journal of heart valve disease, 8(5), 565–566.

Background and aims of the study: Patients with ischemic mitral incompetence have a high operative risk whether the valve is repaired or replaced. The advantage of repair over replacement is unclear in this subgroup of patients.

Methods: Between April 1986 and December 1998, 337 patients underwent surgery for ischemic mitral valve insufficiency. Coronary artery bypass grafting (CABG) was carried out concomitantly in 314 cases (93.2%). Valve repair was performed in 140 patients (operative mortality rate 12.1%). The surgical risk in patients with a left ventricular ejection fraction (LVEF) of 10-30% was higher (operative mortality rate 33.3%) than in those with LVEF >30% (operative mortality rate 8.4%). Actuarial survival rates were 75.4%, 66.8% and 61.7% after 2, 5 and 7 years, respectively. Mitral valve replacement was performed in 197 patients (operative mortality rate 14.2%). The surgical risk in patients with a LVEF of 10-30% (operative mortality rate 30.3%) was greater than in those with a LVEF of >30% (operative mortality rate 11.0%).Actuarial survival rates after replacement were 78.6%, 73.4% 67.2% after 2, 5 and 7 years, respectively.

Results: Our initial analysis showed that, after mitral valve repair, mortality during follow up was greater in patients with residual mitral valve insufficiency of more than grade I. Subsequent outcome was superior when repair was evaluated perioperatively with transesophageal echocardiography. When mitral insufficiency was persistently more than grade I after repair, mitral replacement was performed. A total of 105 patients was analyzed with no or maximum grade I mitral insufficiency following valve repair; actuarial survival rates were 81%, 78.4% and 77.2% after 2, 5 and 7 years' follow up.

Conclusions: Patients with highly impaired LV function and ischemic mitral insufficiency are at high risk during valve repair or replacement, and cardiac transplantation should be considered for this group. However, patients with ischemic mitral insufficiency and moderately impaired LV function can undergo valve repair or replacement with an acceptable prognosis. The goal of mitral valve repair should be to reduce valvular insufficiency to at least grade I. If this is not the case, then the prognosis of repair is worse than after valve replacement. Thus, the surgeon should replace the valve during the same operation.

How to cite: Hausmann, H., Siniawski, H., & Hetzer, R. (1999). Mitral valve reconstruction and replacement for ischemic mitral insufficiency: seven years' follow up. The Journal of heart valve disease, 8(5), 536–542.

Background and aim of the study: Small-sized prostheses may be associated with high transprosthetic gradients, particularly in patients with a body surface area (BSA) >1.70m2, affecting left ventricular mass regression, symptom improvement and long-term survival. However, the influence of such gradients on exercise tolerance has not been clearly defined. The study aim was to verify the utility of cardiopulmonary exercise testing (CPX) in detecting patient-prosthesis mismatch, and to identify the clinical and echocardiographic data that predict exercise tolerance at CPX in patients with a 21mm St. Jude Medical (SJM) aortic prosthesis.

Methods: Twenty patients (one male, 19 females; mean age 66 +/- 9 years) with a 21 mm SJM prosthesis were evaluated by means of 2D echocardiography and CPX at 36 +/- 10 months after operation. Patients were divided into groups on the basis of a BSA of <1.70 m2 (group 1, n = 12) or > or =1.70 m2 (group 2, n = 8).

Results: At echocardiography, left ventricular mass reduction was 16 +/- 10% versus 9 +/- 6% in groups 1 and 2, respectively, mean gradient (MG) was 15 +/- 6 versus 17 +/- 4 mmHg (p = NS), effective orifice area index (EOAi) 0.86 +/- 0.10 versus 0.79 +/- 0.09 cm2/m2 (p = 0.05). At CPX, group 2 patients showed a significantly lower exercise duration (p = 0.02), maximum workload (p = 0.02), peak O2 uptake (p = 0.01), anaerobic threshold (AT) (p = 0.03), ventilatory equivalent for CO2 at AT (p = 0.007), and O2 cost of work (p = 0.03). Group 1 patients showed a ventilatory origin for their effort dyspnea, while group 2 patients showed a significant circulatory component. At multivariate analysis, BSA, age, EOAi and MG were independent predictors of CPX results.

Conclusions: In patients with a 21 mm aortic SJM prosthesis and a BSA > or =1.70m2, CPX allows detection of patient-prosthesis mismatch, in terms of impaired exercise tolerance due to circulatory causes. CPX results can be anticipated on the basis of the patient's BSA, age, EOAi and MG. In these patients, technical solutions allowing implantation of a larger prosthesis should be considered whenever an active lifestyle is anticipated after aortic valve replacement.

How to cite: De Carlo, M., Milano, A., Musumeci, G., Tartarini, G., Biadi, O., Benedetti, M., & Bortolotti, U. (1999). Cardiopulmonary exercise testing in patients with 21mm St. Jude Medical aortic prosthesis. The Journal of heart valve disease, 8(5), 522–529.

Background and aims of the study: Standard measures of hemodynamic severity of aortic valve stenosis vary widely among patients with and without clinical symptoms. Our hypothesis is that valve orifice area alone is not the sole determinant of adverse clinical outcome. Stenotic orifice area ratio is ratio of the cross-sectional stenotic orifice area to the down-stream, ascending aorta cross-sectional area. Determination of workload together with aortic valve orifice area ratio might improve risk stratification among asymptomatic patients with critical aortic stenosis. Accordingly, application of both parameters together might be useful in guiding management decisions in this condition.

Methods: In this study the dependency of transaortic fluid mechanical energy transfer (one component of left ventricular workload) on aortic valve orifice area is shown using modeling and experimental techniques.

Results: For a stroke volume of 62 ml at a heart rate of 60 beats/min, the piston work (analogous to left ventricular work) increased by 17% as the stenotic orifice area ratio decreased from 0.60 to 0.25, by 35% as the ratio fell from 0.25 to 0.20, and by 73% as the ratio fell from 0.20 to 0.10.

Conclusions: As predicted by the fundamental fluid mechanical theory, simulated left ventricular work and energy loss in aortic stenosis are influenced not only by the effective stenotic valve orifice area, but also by the geometry of the inflow and outflow conduits, proximal and distal to the valve. These findings might explain clinically observed discrepancies between valve orifice area and the onset of the classical symptoms of severe aortic stenosis that reflect the left ventricular workload. Consideration of the left ventricular work in addition to the effective valve orifice area should enhance clinical evaluation, prognostication and risk stratification among patients with severe aortic stenosis.

How to cite: Heinrich, R. S., Marcus, R. H., Ensley, A. E., Gibson, D. E., & Yoganathan, A. P. (1999). Valve orifice area alone is an insufficient index of aortic stenosis severity: effects of the proximal and distal geometry on transaortic energy loss. The Journal of heart valve disease, 8(5), 509–515.

Optimal hemodynamic performance is of paramount importance when implanting a prosthesis in a patient with a small aortic annulus. In order to avoid prosthesis size/patient body surface area mismatch, current techniques advocate aortic annulus patch enlargement or the use of a supra-annular prosthesis to ensure the implantation of an appropriately sized aortic valve. We present the first description of mechanical dilatation of a small aortic annulus as a simple alternative method.

How to cite: Bartels, C., & Sievers, H. H. (1999). Successful dilatation of the small aortic root for implantation of a larger valve prosthesis. The Journal of heart valve disease, 8(5), 507–508.

Background and aims of the study: The Ross operation was first performed as a root replacement in 1974, and only limited mid- and long-term results assessing durability and adaptation of the pulmonary root to systemic pressures are available. We reviewed our experience to assess function of the autograft valve and the autograft pulmonary root, and its adaptation to systemic pressures.

Methods: A total of 244 operative survivors (median age 22 years; range: 1 week to 62 years) were reviewed. Clinical follow up (within one year) was available on 98% of cases, and echocardiographic assessment within one year on 93%. Autograft and homograft valve function, aortic annulus diameter, autograft root sinus diameter and ascending aortic diameter were determined on the most recent echocardiogram.

Results: Actuarial freedom from autograft valve degeneration (non-endocarditis autograft valve reoperation or severe autograft valve insufficiency or valve-related death) was 95 +/- 3% at 5 years and 93 +/-4% at 10 years. Actuarial freedom from all valve-related complications (autograft valve degeneration, autograft valve reoperation, homograft valve reoperation or valve-related death) was 90 +/- 4% at 5 years and 83 +/-6% at 10 years. Actuarial freedom from autograft valve replacement was 98 +/- 2% at 5 years and 96 +/- 4% at 10 years. Actuarial survival rate was 98 +/- 2% at 5 years and 86 +/- 9% at 10 years. Aneurysmal dilation of the autograft root occurred in two patients; this was not associated with autograft valve degeneration, and these patients were followed closely.

Conclusions: At 10 years, the Ross root replacement has a low risk of valve degeneration, valve-related complications and autograft valve replacement, and patient survival is excellent. Autograft valve reoperation and homograft valve reoperation have been the only significant late valve-related complications. Techniques to reduce autograft reoperation have been introduced, and hopefully methods to mediate the immunological response to the homograft valve will reduce the incidence of failure. Significant aneurysmal dilation of the pulmonary autograft root is rare.

How to cite: Elkins, R. C., Lane, M. M., McCue, C., & Ward, K. E. (1999). Pulmonary autograft root replacement: mid-term results. The Journal of heart valve disease, 8(5), 499–506.

Background and aim of the study: In asymptomatic prosthetic valve recipients, high-intensity transient signals (HITS) observed with transcranial Doppler (TCD) are a phenomenon of obscure clinical relevance which nature has not yet been elucidated convincingly.

Methods: Eighty-three patients without carotid disease, history of cerebrovascular accidents, and with negative preoperative TCD undergoing either valve replacement (mitral, n = 11; aortic, n = 56; mitral + aortic, n = 6; 40 mechanical prostheses, 29 biological prostheses, 10 homografts) or mitral repair (n = 10) were evaluated prospectively by means of TCD at discharge, three months and one year after surgery, to analyze the presence, incidence and characteristics of HITS. Furthermore, in 12 patients positive for HITS, TCD was repeated during a 30-min period of 100% O2 inhalation.

Results: Twenty-five patients (30%) were positive for HITS at all postoperative controls, although no neurological symptoms were observed. Mechanical prostheses showed a significantly higher incidence of HITS (85%) than biological prostheses (10%, p <0.001), repaired mitral valves (0%, p <0.001) and homografts (0%, p <0.001). At multivariate analysis the presence of a mechanical prosthesis was the only significant predictor of detection of HITS after valve replacement. During O2 inhalation, a significant decrease in the number of HITS per hour (55 +/- 79 versus 22 +/- 31, p = 0.002) occurred, which returned to initial values when room-air breathing was resumed.

Conclusions: Prosthetic valve replacement, particularly when mechanical devices are used, is associated with the generation of HITS which persist throughout the follow up period, but remain clinically silent. The decrease of HITS during O2 inhalation strongly supports the hypothesis of the gaseous nature of such signals and confirms the validity of this method in helping to differentiate gaseous microemboli from solid microemboli in prosthetic valve recipients.

How to cite: Milano, A., D'Alfonso, A., Codecasa, R., De Carlo, M., Nardi, C., Orlandi, G., Landucci, L., & Bortolotti, U. (1999). Prospective evaluation of frequency and nature of transcranial high-intensity Doppler signals in prosthetic valve recipients. The Journal of heart valve disease, 8(5), 488–494.

Background and aims of the study: The composition of microemboli detected as high-intensity transient signals (HITS) by Doppler ultrasound in patients with prosthetic heart valves is still debated. Here, platelet aggregation and HITS were investigated in a sheep model.

Methods: Insonation of the carotid artery was performed in 20 sheep with either a mechanical or a biological mitral valve prosthesis in place. The effect of ICI 170809, a 5HT2a antagonist, on the frequency of HITS and on platelet aggregates, counted in arterial blood smears per nine high-power fields, was assessed at three and six months after valve implantation. The mitral transvalvular gradient was measured by transthoracic echocardiography at three and six months.

Results: Data are expressed as median and interquartile range. At three months, there were 36 (20-114) HITS/h in the mechanical group, and 0 (0-15) HITS/h in the biological group. At six months, there were 21 (0-82) and 0 (0-2) HITS/h, respectively. The occurrence of HITS was unaffected by either ICI 170809, or by duration of implant in either group. Platelet aggregate counts were higher with the mechanical than with the biological valve at three months, but not at six months. ICI 170809 reduced platelet aggregate counts in both valve types; the reduction was not significant in the bioprosthetic valve group. The pressure gradient across the bioprosthesis increased during the study from 2 (2-3) mmHg to 7.5 (6-10) mmHg, but was unchanged in the mechanical valve.

Conclusions: (i) It was confirmed that the frequency of HITS is higher with the mechanical prosthesis than the bioprosthesis; (ii) circulating platelet aggregates in the bioprosthetic valve group tended to increase as structural valve deterioration occurred; (iii) the frequency of HITS was not influenced by either an increase or a decrease in circulating platelet aggregates; and (iv) HITS detected in patients with prosthetic valves are unlikely to be due to circulating platelet aggregates.

How to cite: Raco, L., Belcher, P. R., Sim, I., McGarrity, A., Bernacca, G. M., & Wheatley, D. J. (1999). Platelet aggregation and high-intensity transient signals (HITS) in a sheep model of mitral valve replacement. The Journal of heart valve disease, 8(5), 476–481.

Heart failure is common in patients aged over 65 years, and is the fourth leading cause of hospitalization in the United States. Treatment of congestive heart failure involves remodeling the cardiac chamber with ventricular dilatation. New approaches to resolve this problem include medical therapies (digoxin, diuretics, ACE inhibitors, beta-blockers and phosphodiesterase inhibitors) to stabilize patients, followed by chamber remodeling. As yet, surgical intervention in advanced heart failure has been contraindicated, but newly evolving strategies show significant promise. It appears possible that patients can receive surgical therapy to improve cardiac function, followed by state-of-the-art medical therapy for congestive heart failure. This combined medical/surgical approach has led to the evolution of a new subspecialty within cardiology that deals with the management of heart failure.

How to cite: McCarthy P. M. (1999). New surgical options for the failing heart. The Journal of heart valve disease, 8(5), 472–475.

Background and aims of the study: Having performed our first heart valve replacement in 1960, we began a prospective lifetime follow up service for all patients, contacting them at least annually to determine survivorship and heart valve complications.

Methods: We reviewed isolated aortic (AVR) and mitral (MVR) valve replacements from 1960 to 1993, with follow up to 1998. In total, 2,942 AVR and 1,579 MVR were performed, with 21,742 and 12,142 patient-years of follow up, respectively. Analysis of the results affords an opportunity to demonstrate the usefulness and necessity of certain statistical methods, including multivariable event-free analyses and cumulative incidence functions.

Results: The survival rate was 8% at 30 years for both valve positions. However, an overall survival curve is an artificial composite of patients of increasingly higher risk being served during increasingly safer years of calendar time. One result is that, for AVR, age is not a significant univariate risk factor for operative mortality, but is highly significant after accounting for date of surgery using logistic regression. Long-term mortality is higher for tissue valves than for mechanical valves; but mean age is greater (74 versus 57 years), and after accounting for age using Cox regression, mortality is similar for both valve types. Kaplan-Meier analysis estimates thromboembolism occurrences of 85% for AVR and 95% for MVR at 35 and 34 years, respectively, but the cumulative incidence estimates are only 32% and 41%, respectively.

Conclusions: Prospective follow up for over 35 years has provided an opportunity to illustrate important statistical issues: Multivariate analyses are essential to avoid being misled by excluding important risk factors or including artifactual ones, and the cumulative incidence estimates the percentage of patients who will actually experience a complication.

How to cite: Grunkemeier, G. L., Li, H. H., & Starr, A. (1999). Heart valve replacement: a statistical review of 35 years' results. The Journal of heart valve disease, 8(5), 466–471.