Prosthesis–patient mismatch and clinical outcomes: The evidence continues to accumulate

Impact of the Trifecta bioprosthetic valve in patients with low-flow severe aortic stenosis

Aortic stenosis (AS) is the most common valve disorder in advanced age. Previous reports have shown that low-flow status of the left ventricle is an independent predictor of cardiovascular mortality after surgery. The Trifecta bioprosthesis has recently shown favorable hemodynamic performance. This study aimed to evaluate the effect of the Trifecta bioprosthesis, which has a large effective orifice area, in patients with low-flow severe AS who have a poor prognosis. We retrospectively evaluated 94 consecutive patients with severe AS who underwent aortic valve replacement (AVR). Patients were divided into two groups according to the stroke volume index (SVI): low-flow (LF) group (SVI < 35 ml/m², n = 22) and normal-flow (NF) group (SVI ≥ 35 ml/m², n = 72). Patients’ characteristics and early and mid-term results were compared between the two groups. There were no differences in patients’ characteristics, except for systolic blood pressure (LF:NF = 120:138 mmHg, p < 0.01) and the rate of atrial fibrillation between the groups. A preoperative echocardiogram showed that the pressure gradient was higher in the NF group than in the LF group, but aortic valve area was similar. The Trifecta bioprosthesis size was similar in both groups. The operative outcomes were not different between the groups. Severe patient–prosthesis mismatch (PPM) (< 0.65 cm²/m²) was not observed in either of the groups. There were no significant differences in mid-term results between the two groups. The favorable hemodynamic performance of the Trifecta bioprosthesis appears to have the similar outcomes in the LF and NF groups. AVR with the Trifecta bioprosthesis should be considered for avoidance of PPM, particularly in AS patients with LV dysfunction.

Stented versus Stentless Aortic Valve Replacement in Patients with Small Aortic Root

Objective

The aim of the study was to compare hemodynamic and perioperative outcomes of stented against stentless aortic valve replacement in patients with small aortic root (21 mm or less).

Methods

A comprehensive search was undertaken among the four major databases (PubMed, Embase, Scopus, and Ovid) to identify all randomized and nonrandomized controlled trials comparing stentless to stented bioprosthetic valves in small aortic root patients. Odds ratios, weighted mean differences, or standardized mean differences and their 95% confidence intervals were analyzed.

Results

A total of seven studies with a total of 965 patients fulfilled the inclusion criteria. There was no significant difference in preoperative baselines including mean age between both groups ( P = 0.08), peak aortic valve gradient ( P = 0.06), and effective orifice area ( P = 0.28), whereas higher mean aortic valve gradient in the stented group ( P = 0.007). No difference in cardiopulmonary bypass time ( P = 0.74), aortic cross-clamp times ( P = 0.88), intensive care unit stay ( P = 0.13), and stroke rate ( P = 0.56) were noted. However, stented group of patients showed higher rate of patient prosthesis mismatch ( P = 0.0001) and longer total hospital stay ( P = 0.002). Postoperatively, stentless group showed lower peak and mean aortic valve gradient ( P = 0.003 and P = 0.008, respectively) with a better effective orifice area ( P < 0.00001) at 6 months of follow-up. Mortality rates while in-hospital and at 1 year were similar in both groups ( P = 0.94 and P = 0.86, respectively).

Conclusions

Stentless aortic valves offer superior short-term hemodynamic outcomes in patients with small aortic root when compared with stented aortic valves. Although both groups have similar perioperative complications rates, stentless valves bring about a shorter hospital stay. A further large multicenter randomized controlled trial should address the longer-term benefit of stentless aortic valve over stented valve.

Early hemodynamic performance of the Trifecta™ surgical bioprosthesis aortic valve in Indian patient population: 12 month outcomes of the EVEREST post-market study

BACKGROUND

Indian patients undergoing surgical aortic valve replacement (SAVR) differ from western populations with respect to aortic annulus size and valve disease morphology. The purpose of this post-market, non-randomized observational study was to evaluate the early hemodynamic performance of the Trifecta™ bioprosthesis (Abbott, previously St. Jude Medical, Minneapolis, US) in an Indian patient population.

METHODS

From January 2014 to September 2015, 100 patients (mean age 64.4 ± 7.1 years, 62% male) undergoing SAVR for valve disease (68% stenosis, 7% insufficiency, 25% mixed pathology) were enrolled across 10 centers in India. Patients implanted with a 19-27 mm Trifecta™ valve were eligible to participate and were prospectively followed for 12-months post-implantation. Echocardiographic hemodynamic performance was evaluated at pre-implant, pre-discharge and at 12-months by an independent core laboratory. Adverse events were adjudicated by the study sponsor. Functional status at 12-months was assessed according to NYHA classification. Continuous data was summarized using descriptive statistics (mean &standard deviation,) and categorical data was summarized using frequencies and percentages.

RESULT

Ninety patients (mean age 64.5, 62.2% male) completed the 12-month follow up. Significant improvements in hemodynamic valve performance were reported in 81 patients with available echocardiographic data at 12 months. Compared to baseline at 12-month follow up visit, mean effective orifice area increased from 0.75cm² to 1.61cm² (p < 0.0001), mean pressure gradient reduced to 10.42 mmHg from 51.47 mmHg (p < 0.0001), cardiac output increased from 4.46 l/min to 4.85 l/min (P 0.9254). Compared to baseline, functional status improved by ≥1 NYHA class in 75% of patients at 12 months (95% Clopper-Pearson (Exact) confidence limit [64.6%, 83.6%]). No instances of early mortality (< 30 days from index procedure) or structural valve dysfunction were reported.

CONCLUSION

In an Indian patient population, implantation of the Trifecta™ bioprosthesis is shown to be safe and associated with favorable early hemodynamic performance and improved functional status at 12 months.

TRIAL REGISTRATION

The clinical study has been registered under Clinical Trial Registry-India ( http://www.ctri.nic.in ) and registration number is CTRI/2014/02/004434 registered on 25 February 2014 retrospectively registered.

Aortic valve anatomy and outcomes after transcatheter aortic valve implantation in bicuspid aortic valves

This original clinical research study id focused on description of baseline anatomy and outcomes after transcatheter aortic valve implantation (TAVI) in patients presenting with severe aortic stenosis (AS) and bicuspid aortic valve (BAV). We compared this BAV population with a population of patients with AS and tricuspid aortic valves after a propensity score matching developed by a multivariate logistic regression according to a non-parsimonious approach. Baseline anatomical characteristics were obtained by transthoracic echocardiography (TTE) and multi-sliced computed tomography (MSCT) and compared by chi-square and t-student tests. Outcomes were evaluated by correct fisher test at in hospital and 30 days follow-up. We found that BAV patients presents more complicated baseline anatomy as compared to patients with tricuspid valves. These anatomical features lead to higher procedural complications as the need for a second device implantation. However this does not translate into increase in mortality rate at 30 days follow-up but rather correlate to a lower device success rate.

Multicentre, propensity-matched study to evaluate long-term impact of implantation technique in isolated aortic valve replacement on mortality and incidence of redo surgery

OBJECTIVES

Studies suggest that the use of semicontinuous suture (SC) technique increases the risk of redo valve surgery after aortic valve replacement (AVR). The objective of this study was to identify 30-day mortality, rate of redo operation and long-term outcomes after AVR using either a semicontinuous suture or interrupted suture (IS) technique.

METHODS

A total of 1617 patients from 2 cardiothoracic centres, undergoing isolated AVR between April 2005 and August 2013 were included. AVR was performed using SC technique in 765 patients and IS technique in 852 patients. Data were collected prospectively and follow-up was obtained to date for all patients. We compared 30-day mortality, rate of redo operation and long-term mortality in SC and IS groups. One-to-one propensity-matching analysis was performed using IBM SPSS version 22 to evaluate outcomes.

RESULTS

Four hundred and eleven patients in the SC group were matched to 411 patients in the IS group (total of 822 patients) using propensity-score matching. The baseline characteristics were similar between SC and IS groups after matching. There were no statistically significant differences in 30-day mortality (3.9 vs 2.7%; P = 0.328), long-term mortality at 9-year follow-up (14.4 vs 15.3%; log-rank = 0.524) or rate of redo surgery (2.9 vs 2.0%; P = 0.320) between SC and IS, respectively. However, shorter cross-clamp time (51.9 ± 15.2 vs 60.9 ± 17.6 min; P < 0.001), bypass time (71.3 ± 23.0 vs 81.3 ± 37.8 min; P < 0.001) and the use of larger valve sizes (23.4 ± 2.1 vs 21.9 ± 2.2 mm; P < 0.001) were observed in SC patients compared with IS patients. Multivariate analysis did not show the suture technique as a significant determinant of redo valve surgery.

CONCLUSIONS

This multicentre study demonstrates that neither mortality nor the risk of redo surgery was influenced by the choice of implantation technique using semicontinuous vs interrupted suture techniques. The SC technique allowed shorter operations and larger size valves to be utilized.

Patient-prosthesis mismatch increases the mean platelet volume in patients with aortic valve replacement

PURPOSE

Patient-prosthesis mismatch (PPM) is defined when the ratio of the effective orifice area of the normally functioning prosthetic valve to the body surface area of the patient is <0.85 cm(2)/m(2). The aim of this study was to assess the measurements of the mean platelet volume (MPV) as an indicator of platelet activation in patients with PPM.

METHODS

A total of 109 patients with isolated aortic valve replacement (AVR) procedures with a mechanical prosthesis and a control group from a normal population of 102 people compatible in terms of age and sex were chosen for the study. The AVR group was subdivided into a PPM group (n = 41) and non-PPM group (n = 68). All patients and control participants underwent echocardiographic examinations, with simultaneous measurements of the serum MPV values.

RESULTS

The MPV measurements were significantly higher in the patients with AVR compared to the control group (8.97 ± 0.93 vs. 8.26 ± 0.14, p < 0.001). Higher results were also obtained in the patients with PPM compared to the non-PPM group (9.36 ± 0.61 vs. 8.73 ± 1.01, p < 0.001). The platelet counts were found to be similar in both groups (p > 0.05).

CONCLUSIONS

We have herein shown that the PPM patients had a significantly higher MPV compared to the patients with AVR without PPM and healthy subjects.

Doppler haemodynamics and effective orifice areas of Edwards SAPIEN and CoreValve transcatheter aortic valves

AIMS

Transcatheter aortic valve implantation (TAVI) is a new therapy for severe aortic stenosis in high-risk patients. So far, no reference values for the echocardiographic assessment of this new class of heart valves have been established. The aim of our study was to determine Doppler haemodynamics and the effective orifice area (EOA).

METHODS AND RESULTS

We retrospectively analysed the earliest transthoracic echocardiographic examinations of 146 stable patients after successful TAVI (median 8±20 days). Doppler examinations were analysed for peak instantaneous velocity, peak, and the mean systolic gradient. EOA was determined using the continuity equation. Patients with severe paravalvular aortic or mitral valve regurgitation were excluded. The overall peak instantaneous velocity (n=146) was 2.0±0.4 m/s with a peak systolic gradient of 17.1±7.4 mmHg and a mean gradient of 9.3±4.5 mmHg. The mean EOA was 1.82±0.43 cm2 with an indexed EOA of 1.0±0.27 cm2/m2. In general, all prostheses showed similar values-with the exception of the Edwards Sapien 23 mm which was associated with higher velocities and peak pressure gradients.

CONCLUSION

Our study establishes the normal range for Doppler haemodynamics of four transcatheter aortic valve prostheses. Compared with previously published data of surgically implanted bioprostheses percutaneous valves tend to have similar EOA values but lower mean peak velocities and pressure gradients. In comparison with physiological haemodynamics; however, this new class of heart valves is still associated with a mild obstruction.

Factors affecting survival after mitral valve replacement in patients with prosthesis-patient mismatch

BACKGROUND

The purpose of this study was to determine the impact of prosthesis-patient mismatch on long-term survival after mitral valve replacement.

METHODS

From 1992 to 2008, 765 patients underwent bioprosthetic (325; 42%) or mechanical (440; 58%) mitral valve replacement, including 370 (48%) patients older than 65 years of age. Prosthesis-patient mismatch was defined as severe (prosthetic effective orifice area to body surface area ratio <0.9 cm(2)/m(2)), moderate (0.9 to 1.2 cm(2)/m(2)), or absent (>1.2 cm(2)/m(2)).

RESULTS

Multivariate analysis identified nine risk factors for late death including advanced age, earlier operative year, chronic renal insufficiency, peripheral vascular disease, congestive heart failure, nonrheumatic origin, concomitant coronary artery bypass grafting, lower body surface area, and more severe prosthesis-patient mismatch (lower effective orifice area to body surface area ratio; p < 0.05). For bioprosthetic recipients older than 65 years of age, survival at 5 and 10 years was 30% ± 7% and 0% ± 0% with severe mismatch compared with 43% ± 4% and 21% ± 5% for absent or moderate mismatch, respectively (p = 0.05). For mechanical recipients younger than 65 years of age, survival at 5 and 10 years was 77% ± 4% and 62% ± 6% with moderate or severe mismatch compared with 82% ± 3% and 66% ± 4%, respectively, without mismatch (p = 0.08).

CONCLUSIONS

Severe mismatch adversely affected long-term survival for older patients receiving bioprosthetic valves. With mechanical valves, there was a trend toward impaired survival when mismatch was moderate or severe in younger patients. Thus, selection of an appropriate mitral prosthesis warrants careful consideration of age and valve type.

New concepts in valvular hemodynamics: implications for diagnosis and treatment of aortic stenosis

Aortic valve stenosis (AS) is the third-most frequent heart disease after coronary artery disease and arterial hypertension, and it is associated with a high incidence of adverse outcomes. Recent data support the notion that AS is not an isolated disease uniquely limited to the valve. Indeed, AS is frequently associated with abnormalities of the systemic arterial system, and, in particular, with reduced arterial compliance, which may have important consequences for the pathophysiology and clinical outcome of this disease. Moreover, AS may also be associated with left ventricular systolic dysfunction and reduced transvalvular flow rate, which pose important challenges with regards to diagnostic evaluation and clinical decision making in AS patients. Hence, the assessment of AS severity, as well as its therapeutic management, should be conducted with the use of a comprehensive evaluation that includes not only the aortic valve, but also the systemic arterial system and the left ventricle because these three entities are tightly coupled from both a pathophysiological and a hemodynamic standpoint.

Prosthesis-patient mismatch is less frequent and more clinically indolent in patients operated for aortic insufficiency

OBJECTIVE

To date, no study has focused on the incidence and effects of prosthesis-patient mismatch in patients requiring aortic valve replacement for aortic insufficiency. We hypothesized that the incidence and implications of prosthesis-patient mismatch in patients with aortic insufficiency might be different than for aortic stenosis or mixed disease because the annulus is generally larger in aortic insufficiency and left ventricular remodeling might differ.

METHODS

Ninety-eight patients with lone aortic insufficiency (>or=3+ with a preoperative mean gradient <30 mm Hg) were followed over 7.7 +/- 4.3 years (maximum, 17.5 years) with clinical and echocardiographic assessments. They were compared with 707 patients who had aortic valve replacement for aortic stenosis or mixed disease. Prosthesis-patient mismatch was defined as an in vivo indexed effective orifice area of 0.85 cm(2)/m(2) or less.

RESULTS

Compared with patients with aortic stenosis/mixed disease, patients with aortic insufficiency had approximately half the incidence of prosthesis-patient mismatch (P = .003). Patients with prosthesis-patient mismatch had significantly higher transprosthesis gradients postoperatively. An independent detrimental effect of prosthesis-patient mismatch on survival was observed in patients with aortic stenosis/mixed disease who had preoperative left ventricular dysfunction (hazard ratio, 2.3; P = .03) but not in patients with aortic insufficiency, irrespective of left ventricular function (hazard ratio, 0.7; P = .7). In patients with aortic stenosis/mixed disease with left ventricular dysfunction, prosthesis-patient mismatch predicted heart failure symptoms by 3 years after aortic valve replacement (odds ratio, 6.0; P = .002), but there was no such effect in patients with aortic insufficiency (P = .8). Indexed left ventricular mass regression occurred to a greater extent in patients with aortic insufficiency than in patients with aortic stenosis/mixed disease (by an additional 29 +/- 5 g/m(2), P < .001), and there was a trend for prosthesis-patient mismatch to impair regression in patients with aortic insufficiency (by 30 +/- 17 g/m(2), P = .1).

CONCLUSIONS

The incidence and significance of prosthesis-patient mismatch differs in patients with aortic insufficiency compared with those with aortic stenosis or mixed disease. In patients with aortic insufficiency, prosthesis-patient mismatch is seen less frequently and has no significant effect on survival and freedom from heart failure but might have a negative effect on left ventricular mass regression.

Patient-prosthesis mismatch may be irrelevant after aortic valve replacement with the 19-mm Perimount pericardial bioprosthesis in patients aged 65 years or older

The prevalence of patient-prosthesis mismatch (PPM) and its influence on clinical midterm results were examined in elderly patients whose activity was supposed to be less than that of younger patients. We evaluated valve function and the effects of PPM on the midterm results of the 19-mm Carpentier-Edwards Perimount (CEP) pericardial aortic valve in patients aged 65 years or older. Between August 1996 and May 2005, 51 patients underwent aortic valve replacement with the 19-mm CEP valve. The mean follow-up was 2.4 +/- 1.8 years, involving a total of 134.4 patient-years. The mean age and body surface area at operation were 74.0 +/- 5.0 years and 1.41 +/- 0.14 m(2). There were two (3.9%) operative deaths. Three patients (5.9%) underwent enlargement of their small aortic annuli. The actuarial survival rate at 8 years, including operative mortality, averaged 90.2% +/- 4.7%. The freedom from thromboembolism, reoperation, and valve-related mortality averaged 75.0% +/- 21.7%, 97.8% +/- 2.2%, and 95.3% +/- 3.2%, respectively, at 8 years. High preoperative peak and mean transvalvular pressure gradients were significantly improved after the operation (peak, 93 +/- 35 versus 28 +/- 12 mmHg; mean, 58 +/- 19 versus 17 +/- 7 mmHg, respectively; P < 0.01). The mean left ventricular mass index was reduced from 192 +/- 44 to 142 +/- 46 g/m(2) at late follow-up (P < 0.01). The prevalence of PPM was low (17.6%) when an indexed effective orifice area of less than 0.85 cm(2)/m(2) was taken as the definition of PPM. The clinical results, postoperative pressure gradients, and reduction in left ventricular mass index were not different between the PPM and no-PPM groups. The 19-mm CEP valve produced satisfactory midterm clinical outcomes in patients aged 65 years or older whose activity was supposed to be less than that of younger patients, regardless of the presence or absence of PPM. Moderate PPM was rare and it did not adversely impact on the midterm results. The application of annulus enlargement could be limited to the small number of patients for whom the 19-mm CEP valves are not able to be inserted.

The Quebec Heart Institute: 50 years of excellence in cardiology

The Quebec Heart Institute was established in 1957 at the Laval Hospital in Sainte-Foy, Quebec. Since then, clinical and research activities have made this Institute one of the largest tertiary care cardiology centres in Canada. With its vast catchment area of more than 3,000,000 people, the Institute has developed a strong collaboration with referral physicians centred on clinical, teaching and research interests. The Institute pioneered several aspects of cardiac surgery, invasive cardiology, echocardiography, basic research and, more recently, a network of researchers and clinicians working in the field of 'metabolic cardiology'. The first 50 years of the Quebec Heart Institute are depicted in this overview, which will also introduce this special supplement to The Canadian Journal of Cardiology.

Aortic Valve Replacement With 17-mm St. Jude Medical Prostheses for a Small Aortic Root in Elderly Patients

BACKGROUND

There are few reports about the optimal prosthesis for elderly patients who have small aortic roots with an aortic annular size of less than 19 mm.

METHODS

From October 2004 to October 2006, 11 women aged 70 years or older (mean age, 74.9 +/- 3.5 years) underwent aortic valve replacement with a 17-mm Regent prosthesis (St. Jude Medical, St. Paul, MN), with the size determined using the manufacturer's sizer. Clinical status and the results of preoperative and postoperative echocardiography were evaluated.

RESULTS

The patients had a mean body surface area of 1.33 +/- 0.13 m2. Preoperative average New York Heart Association (NYHA) functional class was 2.5 +/- 0.7. Preoperative echocardiography showed a mean indexed effective orifice area of 0.33 +/- 0.14 cm2/m2 and a left ventricular mass index of 175 +/- 63 g/m2. Seven patients underwent associated procedures. Postoperative ventilation time was 14 +/- 5.6 hours, and the intensive care unit stay was 1.0 +/- 0.4 days. No patients died perioperatively. The NYHA functional class improved to class I in 9 patients. No obstruction of valve opening was observed. A significant increase in the mean indexed effective orifice area (0.87 +/- 0.10 cm2/m2) and regression of left ventricular mass index were found (114 +/- 46 cm2/m2) on postoperative echocardiography.

CONCLUSIONS

Aortic valve replacement in elderly patients with small aortic roots (less than 19 mm) using a 17-mm Regent prosthesis showed satisfactory clinical and hemodynamic results.

Aortic Annular Enlargement During Aortic Valve Replacement: Improving Results With Time

BACKGROUND

Enlargement of the aortic annulus during aortic valve replacement permits insertion of a larger prosthetic valve. Previous reports suggest patch enlargement of the aortic annulus increases operative morbidity and mortality during aortic valve replacement. We compared outcomes for this procedure in a contemporary group of patients with those operated on during an earlier era, to determine whether aortic annular enlargement is still associated with worse outcomes.

METHODS

We reviewed prospectively gathered data on all patients undergoing aortic valve replacement and aortic annular enlargement at our institution from 1995 to 2005 (n = 669). We compared patient outcomes from two consecutive time periods: 1995 through 2000 (n = 360) versus 2001 through 2005 (n = 309). Propensity matching adjusted for baseline differences in a secondary analysis.

RESULTS

Operative mortality was significantly lower in the more recent surgical group (2.9% versus 7.2%; p = 0.013). The rates of perioperative myocardial infarction (1.9% versus 1.1%; p = 0.4), stroke (2.9% versus 3.3%; p = 0.8), and pacemaker implantation (9.1% versus 12.5%; p = 0.16) were similar for both groups (2001 through 2005 versus 1995 through 2000, respectively). The earlier group of patients had a higher prevalence of congestive heart failure, syncope, angina, New York Heart Association class III or IV symptoms, chronic obstructive pulmonary disease, mitral valve disease, and previous cardiac surgery. After adjusting for these baseline differences with propensity matching, the risk of perioperative death remained lower in the contemporary group (3% versus 7.5%; p = 0.04).

CONCLUSIONS

Enlargement of the aortic annulus in the modern era is a safe adjunct to aortic valve replacement, and should be considered in selected patients to avoid patient-prosthesis mismatch.