Exercise Hemodynamic and Functional Capacity After Mitral Valve Replacement in Patients With Ischemic Mitral Regurgitation

Mechanical or biologic prostheses for mitral valve replacement: A systematic review and meta-analysis

Either a mechanical or bioprosthetic valve is used in patients undergoing mitral valve replacement (MVR). However, the optimal mitral prosthesis remains controversial. The aim of this meta‐analysis was thus to compare outcomes between mechanical mitral valve replacement (MVRm) and bioprosthetic mitral valve replacement (MVRb) for MVR patients. We searched Embase, PubMed, Web of Science, and Cochrane Library databases from January 1, 2000 to October 31, 2021 for studies that directly compared surgical outcomes of MVRm and MVRb. A total of 22 studies with 35 903 patients were included in the meta‐analysis (n = 23 868 MVRm and n = 12 035 MVRb). The MVRm group displayed lower long‐term all causes mortality (HR, 0.84; 95% confidence interval [CI]: 0.77−0.91; p < .0001; I² = 51%), and fewer mitral reoperation (hazard ratio [HR]: 0.34; 95% CI: 0.23−0.50; p < .00001; I² = 74%) than MVRb group. However, the MVRm group was associated with a greater risk of major bleeding events (HR: 1.21; 95% CI: 1.14−1.29; p < .00001; I² = 0%), stroke and systemic embolism (HR: 1.20; 95% CI: 1.10−1.32; p < .0001; I² = 0%) in matched or adjusted data. No significant difference was observed between MVRm and MVRb on operative mortality in matched/adjusted group (risk ratios: 0.83; 95% CI: 0.66−1.05; p = .12; I² = 0%). The results were consistent with patients aged under 70 years old. Patients who received a MVRm is associated with 16% lower risk of long‐term mortality and 66% lower risk of mitral reoperation, but 20% greater risk of stroke or systemic embolism, 21% greater risk of major bleeding compared with MVRb in matched/adjusted studies group, which were consistent to patients younger than the age of 70 years who underwent MVR.

Determinants of Aerobic Capacity After Tricuspid Valve Replacement in Congenitally Corrected Transposition of Great Arteries

Background

Systemic tricuspid regurgitation and impaired aerobic capacity are common in adults with congenitally corrected transposition of great arteries (cc-TGA), but it is unknown whether systemic tricuspid valve replacement (sTVR) is associated with improvement in aerobic capacity.

Objectives

The purpose of this study was to determine whether sTVR was associated with postoperative improvement in aerobic capacity as measured by peak oxygen consumption (VO2).

Methods

This is a retrospective cohort study of adults with cc-TGA and ≥moderate tricuspid regurgitation that underwent sTVR and exercise test pre- and post-sTVR (2003-2019). We selected a propensity-matched control group of patients with cc-TGA and ≥moderate tricuspid regurgitation that did not undergo sTVR between exercise tests. Improvement in aerobic capacity was calculated as the difference between baseline and follow-up exercise tests.

Results

The study comprised 48 patients in each group, and both groups had similar peak VO2 at baseline. Compared to the baseline exercise test, the sTVR group had more improvement in peak VO2 (6 ± 4% vs -8 ± 3%-predicted, P = 0.001), and the factors associated with postoperative improvement in peak VO2 were baseline systolic blood pressure (<120 mm Hg), systemic right ventricular global longitudinal strain (<-16%), and preoperative peak VO2 (>60%-predicted).

Conclusions

There was an improvement in aerobic capacity after sTVR in patients with cc-TGA and severe tricuspid regurgitation. The determinants of improvement in aerobic capacity were baseline systolic blood pressure, systemic right ventricular global longitudinal strain, and preoperative peak VO2. Further studies are required to determine whether strict blood pressure control and optimal timing of sTVR based on these indices would result in improved clinical outcomes in this population.

Reduction of tethering distance by papillary muscle tugging approximation with mitral valve replacement for non-ischemic functional mitral regurgitation induces left ventricular reverse remodeling

BACKGROUND

Functional mitral regurgitation (FMR) is caused by left ventricular (LV) remodeling and subsequent tethering of the mitral valve (MV). If LV remodeling is irreversibly advanced, it could not be attenuated by the MV procedure alone, although the additional subvalvular procedure could induce LV reverse remodeling by forcibly reducing MV tethering. This study aimed to assess the anti-tethering effect of papillary muscle tugging approximation (PMTA) on LV reverse remodeling after mitral valve replacement (MVR) for non-ischemic FMR.

METHODS

The study subjects were 19 patients who underwent MVR with and without PMTA [MVR + PMTA (n = 11) and MVR alone (n = 8), respectively] for non-ischemic FMR. The tethering distance (TD) and LV end-systolic volume (ESV) at the preoperative, postoperative, and follow-up periods were assessed in terms of their correlation and time-dependent changes. The intra-LV energy efficiency was also evaluated through vector flow mapping analysis.

RESULTS

TD and ESV were comparable between both procedures preoperatively and did not change after MVR alone. In MVR + PMTA, however, a significant decrease was identified in TD and ESV at the early postoperative and follow-up periods, respectively [TD = 48, 30, and 31 mm (p < 0.001) and ESV = 159, 133, and 82 mL (p < 0.001) at the preoperative, postoperative, and follow-up periods, respectively]. Finally, at follow-up, the extent of change from the preoperative value in ESV significantly correlated with that in TD (ρ = 0.81, p < 0.001 for overall; ρ = 0.93, p < 0.001 for MVR + PMTA; ρ = 0.86, p = 0.011 for MVR alone). The ratio of TD to ESV was also significantly correlated with systolic energy loss to LV stroke work after MVR + PMTA (ρ = 0.81, p = 0.015).

CONCLUSIONS

PMTA for non-ischemic FMR could induce LV reverse remodeling depending on the extent of postoperative TD reduction. A smaller TD to ESV was associated with a higher intra-LV energy efficiency after PMTA + MVR.

Endocarditis risk with bioprosthetic and mechanical valves: systematic review and meta-analysis

OBJECTIVE

Bioprosthetic valves are being used with increased frequency for valve replacement, with controversy regarding risk:benefit ratio compared with mechanical valves in younger patients. However, prior studies have been too small to provide comparative estimates of less common but serious adverse events such as infective endocarditis. We aimed to compare the incidence of infective endocarditis between bioprosthetic valves and mechanical valves.

METHODS

We searched PubMed, Cochrane, EMBASE, Scopus and Web of Science from inception to April 2018 for studies comparing left-sided aortic and mitral bioprosthetic to mechanical valves for randomised trials or observational studies with propensity matching. We used random-effects model for our meta-analysis. Our primary outcome of interest was the rate of infective endocarditis at follow-up.

RESULTS

13 comparison groups with 43 941 patients were included. Mean age was 59±7 years with a mean follow-up of 10.4±5.0 years. Patients with bioprosthetic valves had a higher risk of infective endocarditis compared with patients receiving mechanical valves (OR 1.59, 95% CI 1.35 to 1.88, p<0.001) with an absolute risk reduction of 9 per 1000 (95% CI 6 to 14). Heterogeneity within the included studies was low (I²=0%). Exclusion of the study with maximum weight did not change the results of the analysis (OR 1.57, 95% CI 1.14 to 2.17, p=0.006). A meta-regression of follow-up time on incidence of infective endocarditis was not statistically significant (p=0.788) indicating difference in follow-up times did not alter the pooled risk of infective endocarditis.

CONCLUSIONS

Bioprosthetic valves may be associated with a higher risk of infective endocarditis. These data should help guide the discussion when deciding between bioprosthetic and mechanical valves in individual patients.

Mitral valve prosthesis choice in patients <70 years: A systematic review and meta-analysis of 20 219 patients

BACKGROUND

The optimal mitral prosthesis in young patients is unclear. This systematic review and meta-analysis were performed to compare outcomes between bileaflet mechanical mitral valve replacement (mMVR) and bioprosthesis mitral valve replacement (bioMVR) for MVR patients aged less than 70 years.

METHODS

We searched MEDLINE and EMBASE databases from inception to July 2018 for studies comparing surgical outcomes of mMVR vs bioMVR.

RESULTS

There were 14 observational studies with 20 219 patients (n = 14 658 mMVR and n = 5561 bioMVR). Patients receiving an mMVR were younger with fewer comorbidities including renal failure, dialysis, and less-infective endocarditis (P < .001). The estimated 10-year mortality ranged from 19% to 49% for mMVR and 22% to 58% for bioMVR among studies. Comparing matched or adjusted data, mMVR was associated with lower operative (risk ratio [RR]: 0.61; 95% confidence interval [CI]: 0.39, 0.94; P = .03) and long-term (HR: 0.81; 95% CI: 0.71, 0.92; P = .002) mortality at a median follow-up of 8 years (IQR: 6-10 years). Estimated 10-year risk for mitral valve reoperation ranged from 0% to 8% for mMVR and 8% to 22% for bioMVR among matched/adjusted studies. mMVR was associated with lower matched/adjusted risk of reoperation (HR: 0.35; 95% CI: 0.19, 0.65; P = .001) but with greater risk of bleeding (HR: 1.59; 95% CI: 1.19, 2.13; P = .002) and a trend to greater risk of stroke and embolism (HR: 1.70; 95% CI: 0.92, 3.15; P = .09).

CONCLUSION

Mechanical MVR in patients aged less than 70 years is associated with a lower risk of operative mortality as well as a 20% lower risk of long-term death and 65% lower risk of mitral valve reoperation but 60% greater risk of bleeding compared with bioMVR in matched or adjusted data.

The Choice of Treatment in Ischemic Mitral Regurgitation With Reduced Left Ventricular Function

BACKGROUND

Ischemic mitral regurgitation is a condition characterized by mitral insufficiency secondary to an ischemic left ventricle. Primarily, the pathology is the result of perturbation of normal regional left ventricular geometry combined with adverse remodeling. We present a comprehensive review of contemporary surgical, medical, and percutaneous treatment options for ischemic mitral regurgitation, rigorously examined by current guidelines and literature.

METHODS

We conducted a literature search of the PubMed database, Embase, and the Cochrane Library (through November 2018) for studies reporting perioperative or late mortality and echocardiographic outcomes after surgical and nonsurgical intervention for ischemic mitral regurgitation.

RESULTS

Treatment of this condition is challenging and often requires a multimodality approach. These patients usually have multiple comorbidities that may preclude surgery as a viable option. A multidisciplinary team discussion is crucial in optimizing outcomes. There are several options for treatment and management of ischemic mitral regurgitation with differing benefits and risks. Guideline-directed medical therapy for heart failure is the treatment choice for moderate and severe ischemic mitral regurgitation, with consideration of coronary revascularization, mitral valve surgery, cardiac resynchronization therapy, or a combination of these, in appropriate candidates. The use of transcatheter mitral valve therapy is considered appropriate in high-risk patients with severe ischemic mitral regurgitation, heart failure, and reduced left ventricular ejection fraction, especially in those with hemodynamic instability.

CONCLUSIONS

The role of mitral valve surgery and transcatheter mitral valve therapy continues to evolve.

Long-term outcome after mitral valve replacement using biological versus mechanical valves

BACKGROUND

This study compared long-term outcomes of biological and mechanical mitral valve replacement (MVR) in patients requiring replacement of the mitral valve where repair was not feasible.

METHODS

A single-centre registry of patients receiving MVR between 2005 and 2015 was established. Thirty-day mortality and long-term outcomes were analysed and compared.

RESULTS

Three hundred twenty four patients underwent MVR (265 biological; 59 mechanical valves). Patients receiving biological valves were older (p < 0.001), had a higher log EuroSCORE (p < 0.001) and received less minimally invasive surgery (p < 0.001). Immediate procedural mortality was 1.9%, which only occurred in the biological valve group. At 30 days, 9.0% of patients had died, 4.0% experienced stroke, 8.0% received a pacemaker and 10.5% suffered an acute renal failure. The rate of re-thoracotomy (14.2%) was lower in the biological (12.5%) than in the mechanical valve group (22.0%; adjOR 0.45 [0.20-1.00]; p = 0.050). Frequent long-term complications were stroke (9.2%) and bleeding (4.8%), with bleeding complications being higher in the mechanical valve group (p = 0.009). During the follow-up period biological valves showed a numerically higher survival rate during the first years, which shifted after 3 years in favour of mechanical valves. At 10 years, survival rates were 62.4% vs. 77.1% in the biological and mechanical valve groups (p = 0.769). Hazard ratio after adjustment was 0.833 (95% CI 0.430-1.615).

CONCLUSION

These data confirm that mechanical valve implantation is associated with an increased risk of bleeding. While there was a potential survival benefit during the first years after surgery for patients receiving a biological valves the difference became insignificant after a follow-up of 10 years.

Papillary Muscle Tugging Approximation for Functional Mitral Regurgitation

The surgical approach is challenging for patients with severe functional mitral regurgitation with nonischemic/ischemic dilated cardiomyopathy who are unsuitable for heart transplantation or ventricular assist device implantation. We developed a new surgical treatment named papillary muscle tugging approximation combined with mitral valve replacement. This technique is safe and feasible, with excellent midterm outcomes.

Re-do mitral valve replacement for a bioprosthetic valve with central transvalvular leakage in a patient with ischemic cardiomyopathy: a case report

Transvalvular leakage (TVL) of a prosthetic heart valve is not negligible regurgitant flow in patients with critically low contractile function. Although the opening function of prosthetic valves has been reported, its closing function is not well understood. A man in his 70 s had a history of mitral valve replacement (MVR) with a Magna Mitral® valve for ischemic mitral valve regurgitation. He presented with dyspnea 2 years postoperatively. Echocardiography showed moderate TVL. The pulmonary capillary wedge pressure and cardiac index were 37 mmHg and 1.65 L/min/m², respectively. Because we considered his TVL relevant, we performed re-do MVR with a mechanical valve and papillary muscle approximation and suspension ("papillary muscle tugging approximation"). His cardiac function improved postoperatively; he was discharged with New York Heart Association class I. For MVR in patients with critically low contractile function, prosthetic valves, such as mechanical valves, with small TVL are recommended.

Clinical manifestations, diagnosis, and treatment of ischemic mitral regurgitation: a review

Ischemic mitral regurgitation (IMR) is a frequent complication after acute myocardial infarction (AMI) associated with a worse prognosis. The pathophysiological mechanisms of IMR are not fully understood, but it is known to be a complex process in which ventricular remodelling is the main causal factor. The various imaging techniques in cardiology and echocardiography fundamentally have contributed significantly to clarify the mechanisms that cause and progressively aggravate IMR. At present, different therapeutic options, the most important of which are cardio-surgical, address this problem. Nowadays the improvement in cardiac surgery and transcatheter therapies, have shown a therapeutic advance in IMR management. IMR is a predictor of poor prognosis in patients with heart failure and depressed left ventricular (LV) systolic function. However, it remains controversial whether mitral regurgitation (MR) in these patients is a consequence of dilation and dysfunction of the LV, or whether it contributes to worsening the prognosis of the ventricular dysfunction. Given that echocardiography has a fundamental reference role in the identification, graduation of severity and evaluation of the therapeutics used in the treatment of MR, we are going to focus on it over the rest of the imaging techniques. In contrast to primary MR the benefits of mitral surgery in patients with secondary MR are uncertain. Therefore, we will comment fundamentally on the role of mitral surgery in patients with IMR, with an update of the different surgical interventions available, without forgetting to mention the other therapeutic options currently available.