Early and late stroke after mitral valve replacement with a mechanical prosthesis: risk factor analysis of a 24-year experience

OBJECTIVE: We evaluated risk factors for mortality and stroke after mechanical mitral valve replacement between May 1977 and December 2001. METHODS: Early and late mortality and stroke were assessed. Potential predictors of mortality and stroke were entered into a Cox proportional hazards model. Actuarial survival and freedom from stroke were determined by a log-rank test. RESULTS: Mitral valve replacement was performed in 812 patients. Concomitant procedures included left atrial appendage closure in 493 (61%) patients, tricuspid annuloplasty-replacement in 348 (43%) patients, maze procedure in 185 (23%) patients, plication of the left atrium in 148 (18%) patients, and other procedures in 151 (19%) patients. Five-year actuarial survival was 91.1% +/- 2.3%. Freedom from stroke at 8 years was significantly better in patients with sinus rhythm versus atrial fibrillation (P <.001). Ninety-nine percent of patients with mitral valve replacement combined with a maze procedure were free from stroke, whereas only 89% of patients with mitral valve replacement alone were free from stroke at 8 years after surgical intervention. Seventy-two patients had late stroke; sixty-five patients (90%) were in atrial fibrillation, and 47 (65%) patients had the left atrial appendage closed. Multivariate analysis showed that late atrial fibrillation (odds ratio, 3.39; 95% confidence interval, 1.72-6.67; P =.0001) and omission of the maze procedure (odds ratio, 3.40; 95% confidence interval, 1.14-10.14; P =.003) were the significant risk factors for late stroke. CONCLUSIONS: Persistent atrial fibrillation was the most significant risk factor for late stroke after mechanical mitral valve replacement. Restoration of sinus rhythm with a maze procedure nearly eliminated the risk of late stroke, whereas neither closure of the left atrial appendage nor therapeutic anticoagulation prevented this complication.     

Clinical experience with a porcine aortic valve xenograft for mitral valve replacement

Between March, 1971, and July, 1973, 103 patients underwent mitral valve replacement with a glutaraldehyde-preserved porcine aortic valve mounted on a flexible polypropylene, Dacron-covered stent. Overall operative survival was 95.1%. Actuarial analysis of late postoperative results indicates 92% survival through 2 years, with functional improvement in nearly all patients. The rate of systemic thromboembolism has been approximately 1.7% per patient-year without anticoagulants. No valve failure has occurred. We conclude that this xenograft prosthesis provides a technically and functionally satisfactory valve substitute, the durability of which appears to significantly exceed that of previously available tissue valves for mitral replacement.     

Contemporary trends in aortic valve surgery: a single centre 10-year clinical experience

The purpose of this study is to present a comprehensive profile of the trends in aortic valve replacement at a single institution over the past decade. Prospectively collected data concerning 873 patients undergoing aortic valve replacement (AVR), with and without coronary artery bypass grafting (CABG), were analysed. The patients were divided into three time periods: period I, (1990 to 1993); period II, (1994 to 1996); and period III, (1997 to 2000). Actuarial survival of AVR patients with and without CABG at 7 years was 82.9 +/- 2.4% and 79.1 +/- 3.3% (p = 0.17), respectively. Actuarial survival at 7 years for stentless, mechanical, and stented valve patients were 89.5 +/- 2.7%, 85.5 +/- 2.8%, and 76.0 +/- 3.2%, respectively. There was a significant difference in survival between the stentless and stented valve groups (p = 0.014). Age (63.8 +/- 12.9 yrs, 66.2 +/- 11.0 yrs, 67.9 +/- 10.3 yrs; p = 0.01), the incidence of peripheral vascular disease (5.1%, 10.8%, 16.6%; p = 0.001), and the extent of coronary artery disease necessitating CABG (34.0%, 38.8%, 41.0%; p = 0.05) have increased significantly in the later time period. However, operative mortality has remained constant (4.7%, 4.8%, 4.5%; p = 0.9). Moreover, perioperative complications have decreased significantly (27.4%, 18.0, 16.0%; p = 0.001). Multivariate analysis identified more recent time period as independent protective factor for early mortality and morbidity (period I, RR 1.00; period II, RR 0.47; period III, RR 0.40).     

25-year experience with 456 combined mitral and aortic valve replacement for rheumatic heart disease

BACKGROUND: Valvular heart disease in developing countries resulting from rheumatic fever is disabling and if untreated leads to congestive heart failure and death. Valve replacement has remained the procedure of choice for advanced valve disease. METHODS: Between 1973 and 1997, 456 patients underwent combined mitral and aortic valve replacement. In light of our favorable earlier experience the Starr-Edwards ball valve prostheses were implanted in 90% and 72.8% of mitral and aortic positions, respectively. Follow-up ranged from 1 to 24 years with a median of 8.5 years. RESULTS: The 30-day hospital death rate was 9.2% and late death occurred in 10.1%. A low-intensity anticoagulant regimen was followed to maintain the target prothrombin time at 1.5 times the control value. The actuarial survival at 5, 10, 20, and 24 years was 90.4%, 85.6%, 84.4%, and 82.4% per year, respectively. CONCLUSIONS: In view of the acknowledged advantage of superior durability, increased thromboresistance in our patient population, and its cost effectiveness the Starr-Edwards ball valve is the mechanical prosthesis of choice for advanced combined valvular disease. The low-intensity anticoagulant regimen has offered sufficient protection against thromboembolism as well as hemorrhage.     

Minimally invasive mitral valve surgery: a 6-year experience with 714 patients

BACKGROUND: This study analyzes a single institutional experience with minimally invasive mitral valve operations of 6 years, reviewing short-term morbidity and mortality and long-term echocardiographic follow-up data. METHODS: Seven hundred fourteen consecutive patients had minimally invasive mitral valve procedures between November 1995 and November 2001; concomitant procedures included 91 multiple valves and 18 coronary artery bypass grafts. Of these 714 patients, 561 patients had isolated mitral valve operations (375 repairs, 186 replacements). Mean age was 58.3 years (range, 14 to 96 years; 30.1% > 70 years), and 15.4% of patients had previous cardiac operations. Arterial cannulation was femoral in 79.0% and central in 21%, with the port access balloon endo-occlusion used in 82.3%. Cardioplegia was transjugular retrograde (54.1%) or antegrade (29.4%). Right anterior minithoracotomy was used in 96.6% and left posterior minithoracotomy in 2.2%. RESULTS: Hospital mortality for primary isolated mitral valve repair was 1.1% and 5.8% for isolated mitral valve replacement. Overall hospital mortality was 4.2% (30 of 714). Mean cross-clamp time was 92 minutes and mean cardiopulmonary bypass time was 127 minutes. Postoperatively, median ventilation time was 11 hours, intensive care unit time was 19 hours, and total hospital stay was 6 days. Complications for all patients included permanent neurologic deficit (2.9%), aortic dissection (0.3%); there was no mediastinal infection (0.0%). Follow-up echocardiography demonstrated 89.1% of the repair patients had only trace or no residual mitral insufficiency. CONCLUSIONS: This study demonstrates that the minimally invasive port access approach to mitral valve operations is reproducible with low perioperative morbidity and mortality and with late outcomes that are equivalent to conventional operations.     

Ten years experience with the St. Jude Medical valve prosthesis for mitral valve replacement

During the 10-year period between 1980 and December 1989, isolated mitral valve replacement (MVR) with the St. Jude Medical (SJM) valve prosthesis was performed on 404 patients at our hospital, and a long-term postoperative follow-up was conducted. There were 161 males and 243 females ranged in age from 1 year to 73 years. Early operative mortality was 5.2%. Follow-up period for 383 patients who discharged from the hospital was 1970.7 patient-years. Twenty of these patients died during the follow-up period, and a late mortality rate was 5.2%. During 10 years, thromboembolic event occurred in 8 patients. Four patients had anticoagulant-related bleeding, 4 had paravalvular leak, and 5 underwent re-operations. There was neither structural valve failure nor prosthetic valve endocarditis. Therefore, the actuarial survival rate and the valve-related death-free rate at 10 years were 83.2%, and 96.8%. Of the patients who survived, New York Heart Association class improved significantly (93% in classes II and III preoperatively and 71% in class I postoperatively). Linearized rates for thromboembolism, anticoagulant-related bleeding, and hemolysis were 0.41%, 0.20% and 0.36%/100 patient-years, respectively. The actuarial estimate of incidence free from all complications was 92.0% at 10 years. On the basis of this 10 years' experience, we believe that the SJM valve prosthesis is an excellent mechanical prosthesis for mitral valve replacement, in terms of hemodynamic performance and low thrombogenicity in patients receiving anticoagulants.     

Neurocognitive deficit following aortic valve replacement with biological/mechanical prosthesis.

OBJECTIVE: The aim of this study was to objectively measure neurocognitive deficit following aortic valve replacement with a mechanical or biological prosthesis. MATERIALS AND METHODS: In this prospective, contemporary study we followed 82 consecutive patients undergoing isolated aortic valve replacement with either a mechanical (n=29, mean age=52+/-7 years) or a biological (n=53, mean age=68+/-10 years) valve prosthesis. Neurocognitive function was measured by means of objective P300 auditory evoked potentials (peak latencies, ms) and two standard psychometric tests (Trailmaking Test A, Mini Mental State Examination) before the operation, 7 days and 4 months after the operation, respectively. RESULTS: Since P300 peak latencies increase with age, preoperative P300 measures are lower in patients receiving mechanical valves (360+/-35 ms, mean 52 years) as compared to patients receiving biological valves (381+/-34 ms, 68 years, P=0.0001). Seven days after surgery, P300 peak latencies were prolonged (-worsened) in both groups as compared to preoperative values (mechanical valves: 384+/-36 ms; P=0.0001 and biological valves: 409+/-39 ms; P=0.0001). Although on a different level (-age-related), this development was comparable within both groups (P=0.800). Four months after surgery, P300 peak latencies normalized in the mechanical valve group (372+/-27 ms, P=0.857 versus preoperative), while in contrast in the biological valve group they remained prolonged (417+/-37 ms, P=0.0001). We found no difference within patients receiving different types of biological or mechanical aortic valves. CONCLUSION: Postoperative neurocognitive damage is not reversible in (-elderly) patients with biological aortic valve replacement, while in contrast postoperative neurocognitive damage is reversible in (-younger) patients with mechanical valve replacement. For this contrary development, age seems to be most important, whereas damage related to type of valve prosthesis may be overestimated.     

Long-term survivors after valve replacement with a Starr-Edwards mitral disk valve prosthesis

We report four long-term survivors after valve replacement with a Starr-Edwards (S-E) mitral caged-disk valve. A model 6520 disk valve, size 3M, had been used in all of the four patients. Of the four patients, three underwent replacement of the disk valves 23, 24, and 26 years after mitral valve replacement (MVR), respectively. A pacemaker was implanted in the remaining patient 33 years after MVR. The S-E disk valves were considered hemodynamically slightly stenotic compared with modern bileaflet valves. No disk wear was detected in any of the three explanted valves, and in the remaining patient, a noninvasive evaluation of the disk showed that it was functioning normally. These results suggest the favorable long-term durability of the S-E disk valve.