Standard versus hemodynamic plus 19-mm St Jude Medical aortic valves

Are small-sized mechanical valves adequate for patients with small aortic roots?

AIM

Concerns have been raised over patient outcomes following implantation of small aortic valves (size: 19 and 17 mm). However, in patients with a smaller body surface area, these valves may be adequate. The aim of th study was to assess the hemodynamic and functional performance of these valves and their impact on clinical outcomes in patients with a small aortic root.

MATERIAL AND METHODS

This was a prospective observational study that included all consecutive patients undergoing aortic valve replacement (AVR) with a small-sized aortic valve over a 3-year period. Patients were followed up at 1 week, 6 weeks, and 1 year. Functional and clinical evaluation along with echocardiography was carried out for hemodynamic assessment. In-hospital mortality and hemodynamic outcomes at 1-year follow-up were recorded.

RESULTS

Isolated AVR with a size 17 mm valve was carried out in 15 (25%) and with a 19 mm valve in 45 (75%) patients. The mean annular size was 19.12 ± 2.03 mm. The mean indexed effective orifice area was 1.08 ± 0.16 cm²/m². Satisfactory decrease in peak and mean trans-prosthetic gradient were evident (peak gradient preoperatively was 92.15 ± 26.2 mmHg, and 25.68 ± 12.28 mmHg at 1 year, mean gradient was 55.31 ± 17.41 mmHg preoperatively and 13.71 ± 7.39 mmHg at 1 year). The functional status of patients also showed significant improvement post AVR. Left ventricular ejection fraction pre-operatively was 59.67% ± 10.38% and 59.57% ± 7.98% at 1-week, 59.15% ± 8.17% at 6 weeks, and 59.59% ± 7.48% at 1 year.

CONCLUSION

When confronted with a small aortic root, AVR with a small-sized prosthesis provides a satisfactory hemodynamic and functional outcome. In patients with small body surface area, implantation of a small-sized valve is a viable option.

Effects of pannus formation on the flow around a bileaflet mechanical heart valve

Some patients with a bileaflet mechanical heart valve (BMHV) show significant increases in the transvalvular pressure drop and abnormal leaflet motion due to a pannus (an abnormal fibrovascular tissue) formed on the ventricular side, even in the absence of physical contact between the pannus and leaflets. We investigate the effects of the pannus shape (circular or semi-circular ring), implantation location and height on the leaflet motion, flow structure and transvalvular pressure drop using numerical simulations. The valve model considered resembles a 25 mm masters HP valve. The mean systolic pressure drop is significantly increased with increasing pannus height, irrespective of its implantation orientation. Near the peak inflow rate, the flow behind the pannus becomes highly turbulent, and the transvalvular pressure drop is markedly increased by the pannus. At the end of valve opening and the start of valve closing, oscillatory motions of the leaflets occur due to periodic shedding of vortex rings behind the pannus, and their amplitudes become large with increasing pannus height. When the pannus shape is asymmetric (e.g., a semi-circular ring) and its height reaches about 0.1D (D (= 25 mm) is the diameter of an aorta), abnormal leaflet motions occur: two leaflets move asymmetrically, and valve closing is delayed in time or incomplete, which increases the regurgitation volume. The peak energy loss coefficients due to panni are obtained from simulation data and compared with those predicted by a one-dimensional model. The comparison indicates that the one-dimensional model is applicable for the BMHV with and without pannus.

Early and Mid-term Outcome of the St. Jude Medical Regent 19-mm Aortic Valve Mechanical Prosthesis. Functional and Haemodynamic Evaluation

BACKGROUND AND OBJECTIVES

The aim of the present study is to report the early and mid-term clinical and haemodynamic results of the St Jude Medical Regent 19-mm aortic mechanical prothesis (SJMR-19).

MATERIALS AND METHODS

Between January 2002 and January 2012, 265 patients with aortic valve disease underwent AVR (Aortic Valve Replacement) with a SJMR-19 (St Jude Medical Regent Nr.19). There were 51 males. Mean age was 67.5±12.72years and mean body surface area (BSA) was 1.67±0.14m2. Thirty-six patients required annulus enlargement. The mean follow-up was 34.5±18.8months (range 6-60 months). All patients underwent echocardiographic examination at discharge and within 1 year after surgery.

RESULTS

There were 14 (5.3%) hospital deaths. Six of the hospital deaths were identified in patients undergoing reoperation, significantly higher than patients undergoing first time operation (p=0.0001). Also the postoperative mortality was significantly higher in patients undergoing annulus enlargement versus patients not requiring annulus enlargement (p=0.02). The mean transprosthesis gradient at discharge was 19±9mmHg. At 6 months follow-up the mean NYHA FC class was 1.6±0.5 significantly lower than preoperatively 2.4±0.75 (p <0.0001). The M-TPG was 15.2±6.5mmHg within 1 year after surgery. Left ventricular mass (LVM) and indexed left ventricular mass (LVM_i) were significantly lower than preoperatively The actuarial survival and cumulative freedom from reoperation at 1, 2 and 3 years follow-up were 99.5%, 97.5%, 96.7% and 99.2%, 96.5%, 94.5% respectively. The cumulative actuarial free-events survival at 4 years was 92%. The Cox model identified age (p=0.015), LVEF≤35% (p=0.043), reoperation (p=0.031), combined surgery (p=0.00002), and annulus enlargement (p=0.015) as strong predictors for poor actuarial free-major events survival.

CONCLUSIONS

The SJMR-19 offers excellent postoperative clinical, haemodynamic outcome and LVM_i reduction in patients with small aortic annulus. These data demonstrate that the modern St Jude small mechanical protheses do not influence the intermediate free-reoperation survival.

Does the St. Jude Regent 17-mm Offer Better Outcomes Than the Hemodynamic Plus 17-mm Aortic Valve Mechanical Prothesis?

OBJECTIVE

The aim of the present study is to report the early and mid-term clinical and hemodynamic results of a prospective trial investigating the clinical performance of the St. Jude Medical Regent 17 mm (SJMR-17) versus St. Jude Medical Hemodynamic Plus 17 mm (SJMHP-17).

MATERIALS AND METHODS

Between January 2000 and August 2013, 20 patients (Group I) with aortic valve (AV) stenosis underwent first time AV replacement with a SJMR-17 and nine patients (Group II) underwent AV replacement with a SJMHP-17. The mean follow-up was 58 ± 31 months.

RESULTS

There was one death in Group I. The end-diastolic IVS thickness and end-systolic posterior left ventricle (LV) wall thickness was reduced significantly in boths groups (p = 0.001 and p = 0.006 in Group I and p = 0.007 and p = 0.011 in Group II). The peak and mean transprosthesis gradients (P-TPG and M-TPG) were 29 ± 6.8 mmHg and 17.5 ± 4.5 mmHg in Group I, significantly lower than in Group II (55.2 ± 19.7 mmHg and 28.8 ± 7.7 mmHg). The postoperative left ventricular mass (LVM) and indexed left ventricular mass (LVMi) were reduced significantly in both groups versus the preoperative values. The postoperative LVMi was 114.5 ± 10.6 g/m(2) in Group I versus 127 ± 8 g/m(2) in Group II (p = 0.01). With dobutamine, heart rate, left ventricular ejection fraction, cardiac output, transprosthesis peak, and mean gradients increased significantly in both groups, however, the P-TPG and M-TPG were significantly higher in Group II (p = 0.026 and p = 0.022) despite a non-significant increase of the indexed effective orifice area.

CONCLUSIONS

The SJMR-17 can be employed with satisfactory postoperative clinical and hemodynamic outcomes in patients with small aortic annulus, especially in elderly patients offering better outcome than SJMHP-17.

Hemodynamics of 17-mm vs. 19-mm St. Jude Medical Regent and annulus enlargement

OBJECTIVE

We aimed to compare early and midterm clinical and hemodynamic outcomes of 17-mm vs. 19-mm St. Jude Medical Regent valves with concomitant aortic annulus enlargement.

METHODS

Between 1999 and 2012, 20 patients (group 1) underwent first-time aortic valve replacement with a 17-mm St. Jude Medical Regent valve, and 35 patients (group 2) had a 19-mm valve and concomitant aortic annulus enlargement. The mean follow-up was 81 ± 37 months (range 20-110 months).

RESULTS

There was one death in group 1 vs. 4 in group 2 (p > 0.05). The mean postoperative transprosthetic gradient was 17.5 ± 4.5 in group 1 and 17 ± 6.4 mm Hg in group 2 (p = 0.83), and 37 ± 10.7 and 32 ± 13 mm Hg, respectively, under stress (p = 0.17). Left ventricular mass and left ventricular mass index were reduced and similar in both groups. Postoperative effective orifice area index was higher in group 2 (0.85 ± 0.17 cm(2 )m(-2)) than group 1 (0.76 ± 0.2 cm(2 )m(-2); p > 0.05). A multivariate Cox model identified a 19-mm valve with aortic annulus enlargement (p = 0.032), functional class (p = 0.025), reoperation (p = 0.04), ejection fraction < 35% (p = 0.042), and combined surgery (p = 0.04) as strong predictors of poorer overall event-free survival.

CONCLUSIONS

The 17-mm St. Jude Medical Regent valve may be employed with satisfactory postoperative clinical and hemodynamic outcomes in patients with a small aortic annulus, as an alternative to a larger prothesis with aortic annulus enlargement.

Impact of Prosthesis-Patient Mismatch on Long-Term Survival in Patients With Small St Jude Medical Mechanical Prostheses in the Aortic Position

Background— The impact of aortic prosthesis-patient mismatch (P-PtM) on long-term survival is unclear.

Methods and Results— Between 1985 and 2000, 388 patients at Mayo Clinic in Rochester, Minn, underwent aortic valve replacement (AVR) with 19- or 21-mm St Jude Medical prostheses and had transthoracic echocardiography within 1 year after AVR. Mean age of patients was 62±13 years; 69% were female. Prosthesis effective orifice area (EOA) was derived from the continuity equation. P-PtM was classified as severe (indexed EOA ≤0.60 cm 2 /m 2 ), moderate (0.60 cm 2 /m 2 <indexed EOA≤0.85 cm 2 /m 2 ), or not hemodynamically significant (indexed EOA >0.85 cm 2 /m 2 ). P-PtM was severe in 66 patients (17%), moderate in 168 (43%), and not hemodynamically significant in 154 (40%). Patients with severe P-PtM had a significantly larger body surface area ( P <0.0001), higher mean gradient ( P <0.0001), lower preoperative ( P <0.0001) and postoperative ( P <0.0001) ejection fractions, and lower stroke volume ( P <0.0001) and more often received a 19-mm prosthesis ( P =0.0008) than patients with moderate or no hemodynamically significant mismatch. For patients with severe mismatch, 5-year survival rates (72±6%) and 8-year survival rates (41±8%) were significantly less than for patients with moderate mismatch (80±3% and 65±5%; P =0.026) or no hemodynamically significant mismatch (85±3% and 74±5%; P =0.002). On multivariate analysis after adjustment for other predictors of outcome, severe mismatch was associated with higher mortality (hazard ratio 2.18; 95% confidence interval 1.24 to 3.85; P =0.007) and higher incidence of congestive heart failure (hazard ratio 3.1; 95% confidence interval 1.3 to 7.4; P =0.009) than no hemodynamically significant mismatch.

Conclusions— Severe P-PtM is an independent predictor of higher long-term mortality and congestive heart failure in patients with small St Jude Medical aortic valve prostheses. For patients undergoing AVR who are at risk of severe mismatch, every effort should be made to use a larger prosthesis or to consider a prosthesis with a larger EOA.

Lactatdehydrogenase (LDH) prior and post implantation of ATS® heart valves

Establishing guidelines towards an assessment of prostheses dysfunction using LDH as a marker is difficult as shown by [M. Suedkamp, A.J. Lercher, F. Mueller-Riemenschneider, K. LaRosee, P. Tossios, U. Mehlhorn, Hemolysis parameters of St Jude Medical hemodynamic valves in aortic position, Int. J. Cardiol (95) (2004) 89-93]. In response to their work we would like to add our data concerning ATS valves (AP) and say a word of caution in interpreting an increase of LDH values.

Hemolysis parameters of St. Jude Medical

BACKGROUND

Elevated plasma lactate dehydrogenase (LDH) concentration may reflect hemolysis due to mechanical heart valve dysfunction. Thus, knowledge of LDH levels in patients with properly working prostheses is required. Because hemolysis parameters for the SJM Hemodynamic Plus (HP) and Regent series are currently not available, the purpose of our study was to determine these data.

METHODS

At 12-19 months follow-up after isolated aortic valve replacement with SJM HP(R) or Regent prostheses, we examined 102 patients by transthoracic echocardiography and determined plasma LDH, haptoglobin, bilirubin and hemoglobin.

RESULTS

Five patients with properly working prostheses were excluded because of increased LDH due to non-cardiac reasons. In four patients with paravalvular leakage, LDH was 244, 307, 446 and 628 U/l, respectively. In patients with properly working prostheses, LDH was 287+/-52 (range: 163-374) U/l for HP(R) (n=33) and 274+/-48 (151-386) U/l for Regent valves (n=60, p=0.2). Haptoglobin was <1g/l in all patients; in 91% of HP and 75% of Regent valves, haptoglobin was below detection limit. Bilirubin and hemoglobin as well as red blood cell count (RBC) were normal in all patients except for five patients with renal anemia, two patients with paravalvular leakage and four patients with macrocytosis due to alcohol abuse. There was no correlation between LDH and transvalvular gradient (r=-0.02) or valve size (r=0.25).

CONCLUSIONS

In patients with SJM HP(R) or Regent valves in aortic position, LDH values > 400 U/l indicate valvular dysfunction or leakage if non-cardiac causes for hemolysis are excluded. However, paravalvular leakage can be present without substantially increased LDH. Haptoglobin has no diagnostic value as it is almost always markedly reduced. Hemolysis does not correlate with transvalvular gradient or prosthesis size.

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.

A comparison of the in vivo performance of the 19-mm St. Jude Medical Hemodynamic Plus and 21-mm standard valve

BACKGROUND

In the present study we analyzed the in vivo performance of the 19-mm St. Jude Medical Hemodynamic Plus aortic prosthesis (19HP), evaluated the midterm performance of 19HP in the aortic position, and compared the implantability and hemodynamic characteristics of this valve with those of the 21-mm standard St. Jude Medical valve (21SD) in adult patients with aortic stenosis and a narrowed aortic annulus.

METHODS

From February 1994 to December 1999, 60 patients who underwent isolated aortic valve replacement with either the 19HP (n = 31) or the 21SD (n = 29) were studied. Comparison between the two models included analysis of early and late mortality and morbidity. Pre- and postoperative echocardiography was performed in all patients to evaluate and compare the hemodynamic performance of both prosthetic valves. The postoperative serum lactic dehydrogenase activity was measured in both groups of patients as an indicator of hemolysis.

RESULTS

The mean body surface area was 1.46 +/- 0.16 m2 in the 19HP group and 1.49 +/- 0.13 m2 in the 21SD group (p = 0.1577). Other than female dominance in the 19HP group, there was no statistically significant difference between the two groups in terms of preoperative variables (age, preoperative pressure gradients, and New York Heart Association functional class). The average postoperative peak pressure gradient was 23.3 +/- 10.5 mm Hg in the 19HP group and 27.9 +/- 9.9 mm Hg in the 21SD group (p = 0.0666). There was no hospital death in either group. Six-year follow-up was completed in both groups of patients. Late death occurred in 1 patient in the 19HP group (1.09% per patient-year). Actuarial survival at 6 years was 92.3% +/- 7.4% in the 19HP group, and 100% in the 21SD group (p = 0.33). The linearized complication rate was 1.09% per patient-year and 1.02% per patient-year for thromboembolism, and 1.09% per patient-year and 1.02% per patient-year for anticoagulant-related hemorrhage in the 19HP group and the 21SD group, respectively. Freedom from all complications at 6 years did not show any significant difference between the two groups (p = 0.54). Although left ventricular mass indices decreased significantly after aortic valve replacement in both groups (19HP group, p = 0.0002; 21SD group, p = 0.0006), there were no significant differences in the two indices between the groups after aortic valve replacement (p = 0.999). There was no significant difference in the lactic dehydrogenase level between the two groups (p = 0.4915).

CONCLUSIONS

In vivo hemodynamic performance of the 19HP valve as well as the early and intermediate clinical outcome up to 6 years was satisfactory and corresponded closely to that of the 21SD valve in adult patients. The 19-mm Hemodynamic Plus model can be recommended in patients with a measured 19-mm annulus and this valve will minimize the need for the aortic annular enlargement procedure.

Influence of St. Jude medical valve in patients with aortic stenosis and small aortic annulus on cardiac function and late survival result

This clinical study analyzes our experience of postoperative cardiac function and long-term survival rate in patients with aortic stenosis and small-size St. Jude Medical (SJM) valve. Sixty-eight patients who underwent aortic valve replacement by SJM valve were divided into two groups by preoperative aortic annulus diameter. Group 1 consisted of 44 patients with small aortic annulus and small-size SJM valve (19 mm or 21 mm). In Group 1, small SJM standard valves were implanted in 16 patients, and small SJM Hemodynamic Plus (HP) valves were implanted in 28 patients. Group 2 consisted of 24 patients with large-size SJM standard valve (23 mm or larger). Preoperative left ventricular mass index, left ventricular dimension, the dimension of ascending aorta, and body surface area were significantly smaller in Group 1 than in Group 2. Average age at surgery was older in Group 1 than in Group 2. Effective orifice area index of the SJM valve measured by the manufacturer's data was smaller in Group 1 than in Group 2. Postoperative left ventricular mass indexes of Group 1 (standard valve or HP valve) and Group 2 significantly decreased in comparison with the preoperative mass indexes. Postoperative left ventricular ejection fraction and the peak ejection rate of Group 1 were not different from those of Group 2. The 10 year survival rate of Group 1 was 79%, and the rate of Group 2 was 77%. At 10 years after surgery, freedom from valve-related complication of Group 1 was 80%, and freedom from complication of Group 2 was 81%. Our results demonstrated that small-size SJM valve afforded satisfactory long-term survival rate and valve-related event-free rate for elderly patients with small body surface area and small aortic annulus.

Long-term results for aortic valve replacement with small aortic annulus

We determined whether aortic prosthesis size influences survival and hemodynamic function. Eighty-nine patients who underwent small aortic valve replacement were followed. The small internal orifice area index (IOAI) group was defined as having an internal orifice area/body surface area ratio of < or = 1.3 cm(2)/m(2) (n = 34). The control group was defined as having an IOAI >1.3 cm(2)/m(2) (n = 55). The actuarial survival rate at 10 years was 74.5% in the small IOAI group and 75% in the control group (NS). Freedom from valve-related impairment at 10 years was 87% in the small IOAI group and 85% in the control group (NS). Postoperative pressure gradients were higher in the small IOAI group (p < 0.05). Left ventricular mass index decreased in both groups (albeit nonsignificantly in the small group, but significantly decreased in the control group). The long-term results of aortic valve replacement for patients with small aortic annulus were satisfactory. However, the postoperative pressure gradient through the prosthesis and left ventricular hypertrophy remained at a high level in the small IOAI group.

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.