St. Jude Medical valve prosthesis: an analysis of long-term outcome and prognostic factors

Hemolytic Anemia: Sneaky Cause, Leaky Valve

Intravascular hemolysis is a known complication of prosthetic heart valves. Severe hemolysis is rare (<1%) with the use of newer generation prosthetic valves. This usually occurs due to paravalvular leaks (PVLs). We present a case of hyperbilirubinemia and hemolytic anemia occurring as a result of a PVL of a prosthetic mechanical mitral valve. The patient was a 49-year-old female with a past medical history of rheumatic heart disease status following two mitral valve replacements each with a mechanical prosthesis; she presented with a complaint of worsening fatigue, epigastric pain, nausea, and vomiting. On examination, she had scleral icterus. Heart auscultation revealed a crisp mechanical S1 click and a soft 2/6 systolic murmur in the left lower sternal border. Her abdomen was soft with mild epigastric and right upper quadrant tenderness, and no Murphy’s sign. Her labs revealed a white blood cell count of 7.0 x 10³/microliter, hemoglobin 10.5 g/dL, hematocrit 29.7%, total bilirubin 6.9 mg/dL, direct bilirubin 0.8 mg/dL, alkaline phosphatase (ALP) 62 U/L, aspartate aminotransferase (AST) 79 U/L, and alanine aminotransferase (ALT) 56 U/L. An ultrasound of the abdomen revealed cholelithiasis without pericholecystic fluid collection and no ultrasonographic Murphy’s sign. Magnetic resonance cholangiopancreatography ruled out acute cholecystitis or intra- or extra-hepatic biliary ductal dilatation. A transesophageal echocardiogram showed a well-seated mitral valve prosthesis with a significant PVL and likely moderate mitral regurgitation. The patient was evaluated for possible hemolysis. Lactate dehydrogenase was 1155 U/L, haptoglobin was <30 mg/dL, and reticulocyte count was 5.2%. She underwent a mitral valve re-replacement with a mechanical prosthesis. An echocardiogram after the surgery showed the mechanical prosthesis mitral valve with no residual PVL.

Early postoperative bridging anticoagulation after mechanical heart valve replacement: a systematic review and meta-analysis

OBJECTIVE

To perform a systematic review and meta-analysis of studies evaluating anticoagulation during the early postoperative period following mechanical heart valve implantation.

METHODS

Five literature databases were searched to assess the rates of bleeding and thromboembolic events among patients receiving oral anticoagulation (OAC), both with and without bridging anticoagulation therapy with unfractionated heparin (UFH) or subcutaneous low molecular weight heparin (LMWH). The studies' results were pooled via a mixed effects meta-analysis. Heterogeneity (I(2) ) and publication bias were both evaluated.

RESULTS

Twenty-three studies including 9534 patients were included. The bleeding rates were 1.8% (95% confidence interval CI 1.0-3.3) in the group receiving OAC, 2.2% (95% CI 0.9-5.3) in the OAC + UFH group, and 5.5% (95% CI 2.9-10.4) in the OAC + LMWH group (P = 0.042). The thromboembolic event rate was 2.1% (95% CI 1.5-2.9) in the group receiving OAC, as compared with 1.1% (95% CI 0.7-1.8) when the bridging therapy groups were combined as follows: OAC + UFH and OAC + LMWH (P = 0.035). Most of the analyses showed moderate heterogeneity and negative test results for publication bias.

CONCLUSIONS

Bridging therapy following cardiac valve surgery was associated with a lower thromboembolic event rate, although the difference was small, with considerable overlap of the CIs. Direct comparisons are missing. Bridging therapy with UFH appears to be safe; however, this observation has a risk of bias. Early bridging therapy with LMWH appears to be associated with consistently high bleeding rates across multiple analyses. On the basis of the quality of the included studies, more trials are necessary to establish the clinical relevance of bridging therapy and the safety of LMWH.

Aortic stenosis and mitral regurgitation: implications for transcatheter valve treatment

Moderate or severe mitral regurgitation (MR) is a common finding in patients with severe aortic stenosis (AS). The combination may be a relative indication for double valve surgery, particularly when MR is severe, degenerative, associated with left atrial dilation, chronic atrial fibrillation, or mitral annular calcium. However, in patients for whom open surgery is not desirable, TAVI may provide a reasonable therapeutic strategy with an expectation in selected patients that MR may improve, be better tolerated, or be amenable to staged transcatheter mitral interventions. In this paper, we briefly review the surgical experience with concomitant AS and MR and discuss the potential implications of transcatheter-based heart valve techniques in this patient group.

Management of prosthetic heart valve complications

OPINION STATEMENT

With greater awareness and treatment of valvular heart disease, there are now an increasing number of patients with prosthetic heart valves. However, replacement of a diseased valve with a prosthetic valve creates the opportunity for new and unique complications that once diagnosed require specific treatments. Complications which may occur depend not only on the type of prosthesis but also are influenced by clinical factors that are important to understand and may affect treatment strategies. Tissue prostheses tend to deteriorate over time while mechanical prostheses require anticoagulation with its attendant risks. The rate of serious prosthetic heart valve complications is approximately 3 % per year. They include bleeding, systemic embolization, obstruction due to thrombus or pannus formation, patient-prosthesis mismatch, infective endocarditis, structural deterioration, prosthetic and peri-prosthetic regurgitation, and hemolysis. Importantly, the risk of prosthetic heart valve complications can be reduced by appropriate choices made at the time of surgery such as utilization of the correct prosthesis size and type. In addition, adherence to current guidelines for anticoagulation, endocarditis prophylaxis, and the timing of clinical and echocardiographic surveillance is also important to prevent complications. Should complications occur, rapid diagnosis, usually with echocardiography, is pivotal and can provide important hemodynamic as well as anatomic information critical to determining appropriate treatment and timing of surgical re-intervention if necessary. Optimal treatment of prosthetic heart valve complications remains a challenge and new treatment strategies continue to evolve.

Low-intensity international normalized ratio (INR) oral anticoagulant therapy in Chinese patients with mechanical heart valve prostheses

The purpose of this study was to define the optimal international normalized ratio (INR) intensity of oral anticoagulant therapy in Chinese patients with valve replacement surgery. We studied 1,658 patients who underwent mechanical valve replacement in Beijing Anzhen Hospital; the focus of the study was on correlation between intensity of anticoagulant therapy and thromboembolism/hemorrhage complications. We further followed up 1,508 patients for 46 ± 16 months (range 1-61 months). Average INR was 2.13 ± 0.56, and warfarin dose was 3.09 ± 0.85 mg/day. The incidence rate of anticoagulation-related thromboembolism was 1.17 per 100 patient-years (%/pt-y), and the incidence rate of anticoagulation-related hemorrhage was 2.02%/pt-y. The incidence rate of total complications (i.e., combined thromboembolism and hemorrhages) was 3.24%/pt-y. The rate of total complications in group on INR 1.3-2.3 (aortic valve replacement: 1.3-1.8; mitral valve replacement and double valve replacement: 1.8-2.3) was the lowest among all anticoagulant therapy regimens followed. In conclusion, the relatively low anticoagulant strategy presented above efficiently prevents thrombosis and hemorrhage complications.

Risk-corrected impact of mechanical versus bioprosthetic valves on long-term mortality after aortic valve replacement

OBJECTIVE

Choice of a mechanical or biologic valve in aortic valve replacement remains controversial and rotates around different complications with different time-related incidence rates. Because serious complications will always "spill over" into mortality, our aim was to perform a meta-analysis on overall mortality after aortic valve replacement from series with a maximum follow-up of at least 10 years to determine the age- and risk factor-corrected impact of currently available mechanical versus stented bioprosthetic valves.

METHODS

Following a formal study protocol, we performed a dedicated literature search of publications during 1989 to 2004 and included articles on adult aortic valve replacement with a mechanical or stented bioprosthetic valve if age, mortality statistics, and prevalences of well-known risk factors could be extracted. We used standard and robust regression analyses of the case series data with valve type as a fixed variable.

RESULTS

We could include 32 articles with 15 mechanical and 23 biologic valve series totaling 17,439 patients and 101,819 patient-years. The mechanical and biologic valve series differed in regard to mean age (58 vs 69 years), mean follow-up (6.4 vs 5.3 years), coronary artery bypass grafting (16% vs 34%), endocarditis (7% vs 2%), and overall death rate (3.99 vs 6.33 %/patient-year). Mean age of the valve series was directly related to death rate with no interaction with valve type. Death rate corrected for age, New York Heart Association classes III and IV, aortic regurgitation, and coronary artery bypass grafting left valve type with no effect. Included articles that abided by current guidelines and compared a mechanical and biologic valve found no differences in rates of thromboembolism.

CONCLUSION

There was no difference in risk factor-corrected overall death rate between mechanical or bioprosthetic aortic valves irrespective of age. Choice of prosthetic valve should therefore not be rigorously based on age alone. Risk of bioprosthetic valve degeneration in young and middle-aged patients and in the elderly and old with a long life expectancy would be an important factor because risk of stroke may primarily be related to patient factors.

An Experimental Study of Steady Flow Patterns of a New Trileaflet Mechanical Aortic Valve

Hemodynamic research shows that thrombosis formation is closely tied to flow field turbulent stress. Design limitations cause flow separation at leaflet edges and the annular valve base, vortex mixing downstream, and high turbulent shear stress. The trileaflet design opens like a physiologic valve with central flow. Leaflet curvature approximates a completely circular orifice, maximizing effective flow area of the open valve. Semicircular aortic sinuses downstream of the valve allow vortex formation to help leaflet closure. The new trileaflet design was hemodynamically evaluated via digital particle image velocimetry and laser-Doppler anemometry. Measurements were made during peak flow of the fully open valve, immediately downstream of the valve, and compared with the 27-mm St. Jude Medical (SJM) bileaflet valve. The trileaflet valve central flow produces sufficient pressure to inhibit separation shear layers. Absence of downstream turbulent wake eddies indicates smooth, physiologic blood flow. In contrast, SJM produces strong turbulence because of unsteady separated shear layers where the jet flow meets the aortic sinus wall, resulting in higher turbulent shear stresses detrimental to blood cells. The trileaflet valve simulates the physiologic valve better than previous designs, produces smoother flow, and allows large scale recirculation in the aortic sinuses to help valve closure.

Thromboembolic events after aortic valve replacement in elderly patients with a Carpentier-Edwards Perimount pericardial bioprosthesis

OBJECTIVES

Thromboembolic events after aortic valve replacement with a bioprosthesis were the most frequently occurring complications in elderly patients. Whether this was valve related or dependent on other factors needed further exploration.

METHODS

Five hundred patients with a median age of 73 years were followed retrospectively after aortic valve replacement with a pericardial prosthesis for occurrence of thromboembolism. Of these, 348 also underwent coronary artery bypass grafting. Twenty-five factors were investigated for their potential effect by using univariate and multivariate analysis.

RESULTS

Univariate analysis revealed 6 significant factors: preoperative endocarditis (P =.0001), preoperative cerebrovascular accident (P =.002), use of postoperative warfarin sodium (Coumadin, DuPont Merck; P =.006), arterial hypertension (P =.023), size of valve prosthesis of 27 mm or larger (P =.023), and hospital thromboembolism (P =.040). There was a trend toward increased fatal thromboembolism in patients without medication. With a multivariate analysis, 4 factors remained significant: preoperative cerebrovascular accident (risk ratio, 4.8; P =.0016), warfarin sodium (risk ratio, 3.0; P =.0028), preoperative endocarditis (risk ratio, 5.6; P =.006), and hospital thromboembolism (risk ratio, 6.1; P =.016). Hypertension had a borderline effect. Age, sex, diabetes, 4 coronary artery factors, 3 other valvular factors, atrial fibrillation, and carotid artery disease had no significant effect.

CONCLUSIONS

Some emboli seemed triggered by the valve prosthesis. A proper anticoagulant protocol but also a treatment of hypertension is important in the prevention of thromboembolism after aortic valve replacement with a bioprosthesis. We did not find a significant role of atrial fibrillation and carotid artery disease.

Complications of prosthetic heart valves

Treatment of native valvular heart disease has resulted in an increasing number of patients with prosthetic valves. Although an improvement over the diseased native valve removed at surgery, prosthetic valves have suboptimal hemodynamics; mechanical valves require anticoagulation and tissue valves wear out over time. Serious complications of prosthetic valves occur at a rate of about 2% to 3% per patient-year. Complications include thromboembolism, prosthesis-patient mismatch, structural valve dysfunction, endocarditis, and hemolysis. Prosthetic valve endocarditis is a lethal disease with mortality rates of 50% to 80% even with appropriate therapy. Echocardiography now provides detailed information on valve function and hemodynamics, allowing early detection of complications. Many of these complications can be prevented by choosing the optimal valve at the time of surgery, rigorous control of anticoagulation and adherence to established anticoagulation guidelines, dental hygiene and endocarditis prophylaxis, and periodic echocardiographic monitoring by a cardiologist.

The optimal intensity of vitamin K antagonists in patients with mechanical heart valves: a meta-analysis

OBJECTIVES

The purpose of this study was to compare two different intensities of vitamin K antagonists (VKA) among patients with mechanical heart valves using meta-analytic techniques.

BACKGROUND

Patients with mechanical heart valves are at increased risk for valve thrombosis and systemic embolism, which can be reduced by VKA. The range of optimal intensity of VKA is still a matter of debate.

METHODS

A computerized search in the PubMed database was made for relevant articles. A meta-analysis was performed of all eligible studies with data on the incidences of thromboembolic and bleeding complications in patients with mechanical heart valve prostheses during different intensities of VKA therapy. The studies were classified into low-intensity VKA therapy (mean target international normalized ratio [INR] of 3.0 or lower) or high-intensity VKA therapy (mean target INR above 3.0).

RESULTS

Thirty-five eligible studies were identified, including in total 23,145 patients, who were studied for 108,792 patient-years. For patients with an aortic valve, high intensity resulted in a lower incidence of thromboembolic events (risk ratio [RR] = 0.73, p < 0.0001); however, the incidence of bleeding was increased (RR = 1.23, p < 0.0001). In the mitral valve group, the incidence rate for thromboembolism was lower in the high-intensity group (RR = 0.74, p < 0.0001), without a significantly increased bleeding incidence (RR = 1.08, p = 0.0524). The total number of thromboembolic and bleeding events was decreased in the high-intensity group compared with low-intensity VKA therapy for both aortic and mitral valve prostheses (RR = 0.94 [p = 0.0067] and 0.84 [p < 0.0001]), respectively.

CONCLUSIONS

This meta-analysis shows that both aortic and mitral valves will benefit from a treatment strategy with a target INR higher than 3.0.

"Our complication rates are lower than theirs": statistical critique of heart valve comparisons

OBJECTIVES

From the widely differing complication rates published for every heart valve, is it possible to determine a true rate for each valve and to compare the rates of two different valves? We investigated this question for the two most popular bileaflet valves.

METHODS

Aortic valve data were abstracted from 14 St Jude Medical (St Jude Medical Inc, Minneapolis, Minn; 33,125 patient-y) and 11 Carbomedics (Sulzer Carbomedics Inc, Austin, Tex; 19,141 patient-y) series, and mitral valve data were abstracted from 11 St Jude Medical (21,553 patient-y) and 8 Carbomedics (8368 patient-y) series. Regression analysis was used to accommodate heterogeneity among rates with the same valve model, to estimate hazard ratios and 95% confidence intervals for the valve model effect, and to incorporate other series-level risk factors.

RESULTS

Most of the complication rates with both valve models exhibited significant heterogeneity. For thromboembolism and bleeding, the relative risks for valve model were not significantly different from unity. Valve thrombosis rates exhibited less heterogeneity: the Carbomedics valve had a lower rate in the aortic position (hazard ratio 0.2, 95% confidence interval 0.1-0.6) and a higher rate in the mitral position (hazard ratio 1.9, 95% confidence interval 1.0-3.8).

CONCLUSIONS

Unlike simple weighted averages of valve complication rates, regression methods can incorporate heterogeneity related to center effects and allow for inclusion of other risk factors. Thromboembolism and bleeding rates were not significantly different with St Jude Medical and Carbomedics valves. Valve thrombosis appeared to differ between the two valves, but the absolute differences in rates were small. Because of the variability among rates with the same valve, statistical comparisons must be interpreted cautiously.

Blood compatibility of a newly developed trileaflet mechanical heart valve

An ideal heart valve prosthesis, which has both the flow dynamic properties and blood compatibility of a tissue valve prosthesis and the durability of a mechanical prosthesis, does not exist. The Triflo trileaflet mechanical heart valve (MHV; Triflo Medical Inc., Irvine, CA) is a newly developed MHV prosthesis with the following design goals: central flow, minimal flow disturbance and stasis around the hinge region, and durability. The current study was conducted to evaluate the blood compatibility of a 29 mm Triflo MHV in the mitral position of eight calves for 5 months without any postoperative anticoagulation. Whole blood platelet aggregometry and the Xylum Clot Signature Analyzer (Xylum Corporation, Scarsdale, NY) were used to evaluate the postoperative changes in platelet and coagulation functions. Full autopsies, histological examinations of major internal organs, and scanning electron microscopy analyses of the explants were performed. Early termination occurred in two cases; one was because of valve thrombosis on the 25th day, and the other was killed because of a nonvalvular complication on the 105th day. The valve thrombosis was attributed to prolonged ventricular fibrillation at the time of valve replacement surgery. Whole blood platelet aggregometry and clot signature analyzer parameters did not show any sign of activation of platelets or the coagulation system. No hemolysis was observed. There was no macroscopic valve thrombosis or embolism observed in the remaining seven cases. Scanning electron microscopy analyses showed clean leaflet and valve ring surfaces, with only occasional minute platelet aggregations. Excellent blood compatibility of the Triflo MHV was demonstrated in this study.

Ten year clinical experience with the CarboMedics heart valve implants

We reviewed the histories of 144 patients who underwent heart valve replacement with the CarboMedics prosthesis from 1990 to 2000. There were 74 males and 70 females, with a mean age of 52 years, including 69 aortic valve replacements, 48 mitral valve replacements, and 27 double (aortic and mitral) valve replacements. The mean duration of follow-up was 6.5 years. Early mortality was 7.6% (11 patients). Late deaths occurred in 14 patients, including cardiac-related late deaths in 9 and valve-related deaths in 3. The survival rate including early deaths was 84.7 +/- 3.2% at 5 years and 78 +/- 4.1% at 10 years. Preoperative New York Heart Association Class IV (p = 0.0001) was found to be a significant predictor of cardiac-related late death. Freedom rate from complications at 10 years were embolism 84.7 +/- 4.2% (linearized rate 1.8% per patient year), valve thrombosis 92.7 +/- 2.7% (linearized rate 0.8% per patient year), bleeding 95.6 +/- 2.6% (linearized rate 0.4% per patient year), reoperation 85.9 +/- 4% (linearized rate 1.5% per patient year), valve endocarditis 98.7 +/- 1.3% (linearized rate 0.1% per patient year), and nonstructural dysfunction 90 +/- 3.5% (linearized rate 1% per patient year). There was no structural deterioration. The early and long-term results with the CarboMedics heart valve implantation were acceptable, but valve thrombosis remains a concern in the present study. Further investigation for optimal anticoagulation therapy is necessary to reduce the incidence of valve thrombosis as well as embolic and bleeding complications.

Preliminary experience with the St. Jude Medical Regent mechanical heart valve in the aortic position: early in vivo hemodynamic results

BACKGROUND

The St. Jude Medical Regent is a new generation mechanical aortic valve.

METHODS

Between March 2000 and July 2001, this valve was implanted in the aortic position in 40 patients (21 men; mean age 59.1 +/- 9.0 years). Preoperatively, 24 patients (60%) were in New York Heart Association functional class III or IV. Eighteen patients (45%) underwent associated procedures. Mean valve size was 21.4 +/- 2.4 mm. The mean duration of follow-up was 8.5 +/- 4.5 months (range, 1 to 16 months).

RESULTS

There were no operative deaths. Early complications included one reoperation for bleeding and one transient low output syndrome. Valve replacement was followed by a significant reduction in mean and peak transaortic gradients over time (p < 0.001) and analysis of variance failed to demonstrate statistical differences between valve size over time (p = not significant). A significant reduction in left ventricular hypertrophy occurred over time (p = 0.01) in all valve sizes (p = not significant between groups): baseline left ventricular mass index was 194 g/cm2; it reduced by 22 g/cm2 (p = 0.006) at discharge. Left ventricular mass index decreased from 172 +/- 55 g/cm2 to 156 +/- 44 g/cm2 (p = 0.03) from discharge to 2 months. Further reductions were not significant. Relative wall thickness decreased from 0.57 +/- 0.13 preoperatively to 0.42 +/- 0.06 at discharge (p = 0.001), and again at 2 months (-0.2; p = not significant), and at 1 year (-0.02; p = not significant).

CONCLUSIONS

The early experience with the St. Jude Medical Regent valve has been satisfactory.

Clinical outcome in patients with 19-mm and 21-mm St. Jude aortic prostheses: comparison at long-term follow-up

BACKGROUND

Small-sized prostheses for aortic valve replacement may result in residual left ventricular outflow tract obstruction. Aim of the study was to verify whether implantation of 19-mm versus 21-mm St. Jude Medical standard prostheses (St. Jude Medical, Inc, St. Paul, MN) influences long-term clinical outcome.

METHODS

Two hundred twenty-nine patients who underwent aortic valve replacement with 19 mm (group 1, 53 patients) or 21-mm St. Jude Medical standard prostheses (group 2, 176 patients) were included in the study. Mean follow-up of current survivors was 10+/-4 years.

RESULTS

Operative mortality was 7.5% in group 1 and 8.5% in group 2. At discharge, an important patient-prosthesis mismatch (effective orifice area index < or = 0.60 cm2/m2) was present in 18% of group 1 versus 5% in group 2 (p = 0.004). Among patients with body surface area less than 1.70 m2, such mismatch was present in 15% of group 1 versus 2% of group 2 (p = 0.008). At last follow-up New York Heart Association (NYHA) functional class (p < 0.001), left ventricular mass reduction (p = 0.02), mean (p = 0.002) and peak transprosthetic gradients (p < 0.001), and effective orifice area index (p = 0.005) were significantly better in group 2. Freedom from sudden death (92%+/-5% vs 99%+/-1%, p = 0.01), valve-related death (84%+/-6% vs 90%+/-5%, p = 0.02), and cardiac events (56%+/-13% vs 86%+/-4%, p = 0.008), were significantly lower in group 1. Effective orifice area index was an independent predictor of late cardiac events.

CONCLUSIONS

Although long-term results after aortic valve replacement with small-sized St. Jude Medical standard prostheses are satisfactory, 19-mm valve recipients show a high prevalence of important patient-prosthesis mismatch with less evident functional improvement and higher rate of cardiac events, suggesting a very cautious use of this prosthesis.

Repeated thromboembolic and bleeding events after mechanical aortic valve replacement

BACKGROUND

The choice of a valve substitute in young adults requires a decision balancing the risks of long-term anticoagulation versus reoperation(s). This article analyzes the long-term risk and determinants of thromboembolic (TE) and bleeding (BLE) complications after mechanical aortic valve replacement (AVR).

METHODS

From December 1963 to January 1974, 249 patients survived a mechanical AVR at our institution. Mean age was 41.8+/-12.4 years and 81% (n = 202) were male. Ball valves were implanted in 24% (n = 61) and disc valves in 76% (n = 188). Patients were anticoagulated with vitamin K antagonists and dipyridamole. A total of 4,855 patient-years was available for analysis. Mean follow-up was 19.5+/-9.4 years and was 100% complete. Analyses were performed with Kaplan-Meier and multivariable Cox regression methods.

RESULTS

One hundred and two patients had one TE or BLE postoperative event and 58 patients had two postoperative events. Six patients had more than five postoperative events. Freedom from a first postoperative event was 74.8%+/-2.9%, 55.3%+/-3.5%, and 46.8%+/-4.0% at 10, 20, and 30 years, respectively. Freedom from a second postoperative event was 45.4%+/-5.4%, 29%+/-6.0%, and 23.2%+/-7.1% at 10, 20, and 30 years, respectively. Multivariate predictors for TE or BLE complications were ball valve (Odds Ratio (OR) = 2.9), postoperative endocarditis (OR = 2.2), and any surgery (OR = 2.2). The incidence of events was highest the first 5 postoperative years.

CONCLUSIONS

The risk of adverse events is highest the first 5 postoperative years. Once an event has occurred, the risk for a second event is increased. The incidence and frequency of events is substantial and should be considered in the choice of a valve substitute.

Standard aortic St. Jude valve at 18 years: performance profile and determinants of outcome

BACKGROUND

The standard St. Jude disc valve has been in use for 20 years and remains the dominant mechanical valve of today. With nearly 19 years of follow-up, the present large series could indicate the performance profile and its determinants in the very long term.

METHODS

A detailed follow-up was performed to a maximum of 18.6 years in 694 patients aged 15 to 83 years who undervent aortic valve replacement (AVR) with the standard St. Jude valve during 1980 to 1993. The Cox regression analysis was used to identify independent determinants of outcome in the aortic stenosis (n = 490) and regurgitation (n = 204) groups.

RESULTS

Overall survival was 58%, 39%, and 37% at 10, 15, and 18 years, respectively. Only 12% of deaths (0.60%/ patient-year) were related to the valve with a 15-year freedom of 91%. Embolism (1.18%/patient-year) and anticoagulant-related bleeding (2.24%/patient-year) were the dominant complications with 10-year/15-year freedoms of 90%/80% and 85%/72%, respectively. Only 24% of bleeding events were classified as major. Valve thrombosis occurred in 2 patients (0.04%/patient-year): 1 did not receive vitamin K antagonist treatment and International Normalized Ratio was below target level in the other. There were no mechanical failures. Endocarditis (0.42%/patient-year) and paravalvular leak (0.42%/ patient-year) occurred with 15-year freedoms of 92% and 96%, respectively, with a relation between the latter (but not the former) and preoperative endocarditis in the regurgitation group. Freedom from serious complications (2.33%/patient-year) and all complications joined (4.33%/ patient-year) were 72% and 54%, respectively, at 15 years with a 96% freedom from redo AVR (0.36%/patient-year). Age- and heart-related variables were independent risk factors for mortality, thromboembolism, bleeding, serious complications, and all complications joined. Small valve (19 and 21 mm) adversely affected serious and all complications in the regurgitation group.

CONCLUSIONS

With a follow-up approaching 2 decades and exhibiting a low rate of valve-related deaths, acceptable low thrombogenicity, and absence of mechanical failure, the standard aortic St. Jude disc valve sets the standard for contemporary mechanical valves.

Performance profile of the Starr-Edwards aortic cloth covered valve, track valve, and silastic ball valve

OBJECTIVE

The Starr-Edwards aortic ball valve has passed 30 years of clinical follow-up. A detailed account of the long-term performance from a large series could thus give valuable guidance in managing patients who are still alive, depict the total remaining life-span after aortic valve replacement (AVR) for the average patient, and set a record yet to be matched by modern disc valves.

METHODS

A detailed follow-up to a maximum of 31.1 years was performed for 717 patients who underwent their first AVR during 1965-1993 with a Starr-Edwards silastic ball valve (N = 355), a cloth covered valve (N = 164) or a track valve (N = 198) with a total of 7254 patient-years at risk.

RESULTS

Patients who received a silastic ball valve were older (average 60 vs. 58 years), had more endocarditis (9%) and more secondary kidney failure (24%) preoperatively than the other patients. The three valve types did not differ as regards long-term survival or freedom from complications and only 15% of late deaths were related to the valve. For the silastic ball valve cumulative freedoms at 10 and 25 years were 59 and 20% from all deaths (crude survival), 85 and 80% from thromboembolism, 87 and 70% from bleeding, 98 and 94% from endocarditis, 96 and 95% from redo AVR and 68 and 51% from all valve related complications joined. There were no instances of structural failure apart from wear of the cloth covering the cage struts of the cloth covered valves. Incidences of haemolysis (0.10%/patient-year) and valve thrombosis (0.06%/patient-year) were low for the silastic ball valve. Analysis of relative survival for the silastic ball valve indicated excess mortality relative to a matched background population only during 1st and 13th postoperative year. Apart from heart related factors and age, independent incremental risk factors for mortality and the various complications included, not valve type, but valve size index (valve size divided by body surface area) < or = 13 mm/m2.

CONCLUSIONS

The Starr-Edwards aortic ball valves, not least the currently available silastic ball valve, are durable through the remaining life time of the patients and able to secure near normal age and sex specific survival provided valve and patient size mismatch is avoided.

Outcome analysis of 245 CarboMedics and St. Jude valves implanted at the same institution

BACKGROUND

Thromboembolism and valve-related death are major complications associated with prosthetic valve implants, but it is difficult to evaluate the relative incidence of these complications based on studies in which the implantation of only one valve is reported from any given institution. We therefore report the outcome of patients implanted at our institution during the same time period with either the recently released CarboMedics (CM) or the St. Jude Medical (SJ) valve prostheses.

METHODS

Between October 1994 and January 1996, 245 consecutive patients received either SJ (116 patients) or CM (129 patients) valves at our institution. Follow up of these patients was 99.6% complete, for a total of 318.5 cumulative patient-years (median follow-up, 1.4 years).

RESULTS

The 30-day mortality rates for SJ and CM implants were 3.4% and 3.1%, respectively. Actuarial survival and freedom from valve related mortality rates at 1.5 years for SJ and CM valves were 94%+/-2% versus 86%+/-3% (p = 0.03) and 100% versus 94%+/-2% (p = 0.005), respectively. There was no structural valve failure for either implant, but there were five thrombosed valves in the CM group and none in the SJ group (p = 0.04). All thrombosed valves were mitral (four mitral valve replacement, one aortic and mitral valve replacement). Two of the thrombosed valves were successfully explanted, whereas the three remaining patients died. Freedom from a thromboembolic event in the mitral position at 1.5 years, including thrombosed valves was 97%+/-3% and 83%+/-5% for SJ and CM valves, respectively (p = 0.04).

CONCLUSIONS

The results of this study suggest that further evaluation of thromboembolic outcomes after CM compared with SJ valve implantation is warranted.

Mitral valve replacement with the St. Jude Medical prosthesis: a 15-year follow-up

BACKGROUND

A retrospective study was conducted to analyze the results of St. Jude Medical mitral valve replacement.

METHODS

From January 1979 to December 1989, 870 patients (54% women, 46% men; mean age, 55.8 +/- 6.2 years) underwent mitral valve replacement with the St. Jude Medical prosthesis. Of these operations 616 were isolated mitral valve replacements and 254 were double valve replacements. Coronary artery bypass grafting was performed concomitantly in 55 patients (6.3%).

RESULTS

Overall, early mortality was 5.05%, with 4.2% for the isolated mitral valve procedure and 7.08% for the double valve replacement. Follow-up at 15 years was complete in 859 patients (98.74%). Mean follow-up time was 93.5 months, for a total of 6,436 years. Actuarial survival at 15 years was 59.5% +/- 5%, 60.5% +/- 6%, and 56.9% +/- 9%, for the entire group, the isolated mitral valve and double valve procedures, respectively. Multivariate analysis identified age, sex, hospital stay, and preoperative mitral regurgitation as independent prognosis factors for overall mortality. Of 606 patients alive at the latest follow-up, the New York Heart Association class improved significantly (from 67% class III/IV before the operation to 88% class I/II after the operation). All patients received warfarin to maintain an international normalized ratio between 3.5 and 4. The linearized rates (% per patient-year) of thrombosis, thromboembolism, and major hemorrhage were, respectively, 0.21, 0.75, and 0.94 for the entire group; 0.18, 0.67, and 0.88 for the isolated mitral valve operation; and 0.15, 0.92, and 1.08 for the double valve replacement. For the entire group the freedom from thrombosis and thromboembolism at 15 years was 98.1% +/- 1% and 88% +/- 4%, respectively. No case of structural dysfunction occurred. The freedom from paravalvular leak and endocarditis at 15 years was 95.3% +/- 2% and 97.3% +/- 2.4%, respectively. The probability of remaining free from reoperation at 15 years was therefore 95.6% +/- 2.5%.

CONCLUSIONS

These results confirm that the St. Jude Medical valve is a reliable prosthesis with very low thrombosis and thromboembolism rates, allowing the use of a low dose of anticoagulation with an international normalized ratio of about 3.

Long-term follow-up of St. Jude Medical prosthesis in a young rheumatic population using low-level warfarin anticoagulation: an analysis of the temporal distribution of causes of death

This study assesses the long-term (mean 52+/-24 months) performance of the St. Jude Medical (SJM) valve in 200 young (mean age 31+/-13 years) rheumatic patients on low-level warfarin anticoagulation combined with dipyridamole. Follow-up was 95% complete and comprised 867 patient-years. There were 33 deaths (3.8%/patient-year). Death was valve related in 12 cases and due to left ventricular dysfunction in 10. Death due to left ventricular dysfunction occurred earlier after surgery than death due to other causes (10+/-7 vs 29+/-18 months, p <0.005); these patients had larger preoperative left ventricular dimensions than the rest of the group (end-systolic diameter 51+/-13 vs 37+/-16 mm, end-diastolic diameter 66+/-13 vs 50+/-19 mm, p = 0.006). Actuarial probability of survival was 81% at 86 months and probability of event-free survival was 71%. The median international normalized ratio was 1.88+/-0.54. Thromboembolism (13 events) occurred at a linearized rate of 1.5%/patient-year. There were 11 major bleeding episodes (1.3%/patient-year), 4 cases of prosthetic valve endocarditis (0.8%/patient-year), and 12 paraprosthetic leaks (1.4%/patient-year). No valve obstructions or reoperations occurred. Thus, the SJM valve performs well on low-level anticoagulation combined with dipyridamole. Left ventricular dysfunction was a common cause of death in the early postoperative period.

Semicontinuous suture technique for all prosthetic valve insertions: the "hoist" technique

The semicontinuous suture technique as an alternative method in valve replacement is described. This specific technique is applicable for both adults and children requiring valvular prosthetic operations. This method combines advantages of the continuous and interrupted suture techniques.

Mechanical versus biological isolated aortic valvular replacement after the age of 70: equivalent long-term results

OBJECTIVE

In order to evaluate the long-term outcome of valvular substitutes in the elderly, we retrospectively analyzed two comparative groups of patients consecutively operated on by the same team for an isolated valvular aortic replacement using either a mechanical or a pericardial prosthesis.

METHODS

From 1982 to 1996, 206 patients over 70 years (mean 76.5+/-4.4) underwent an isolated aortic valvular replacement using either a St. Jude Medical (Group I, n = 93) or a Mitroflow (Group II, n= 113) prosthesis depending on the surgeon's preference at the time of surgery. Both groups matched for the following pre-operative variables: sex ratio, type of aortic valve disease, NYHA status, cardiac rhythm, mean pulmonary arterial pressure, left ventricular end-diastolic pressure, LV-AO gradient, cardiac index and ejection fraction.

RESULTS

Given an early mortality rate of 6.4% in Group I and 4.4% in Group II (NS), follow-up (mean 4.4+/-3.7 years in Group I and 5.3+/-3.1 years in Group II) was 100% complete. Actuarial survival was 69.9+/-6 and 70.2+/-4.6% at 5 years for Group I and Group II, respectively, and 49.6+/-7.7 vs. 51.4+/-6.3% at 10 years (NS). Freedom from valve-related death was 86.5+/-4.8% in Group I vs. 82.7+/-4% in Group II at 5 years (NS) and 66.7+/-8.7 vs. 66.3+/-7% at 10 years (NS). There were no anticoagulant-related deaths or severe accidents in Group 1. A secondary valvular replacement was necessary in 4 patients in Group II vs. none in Group I.

CONCLUSION

The study shows a similar late survival in both groups, with a strikingly low incidence of anticoagulant-related deaths in this population. Given a higher rate of reoperation after biological valve replacement, the use of mechanical valve in this aging population seems to be a valid option.