Vasoactive drugs in chronic regurgitant lesions of the mitral and aortic valves

Predictive nomogram for 28-day mortality risk in mitral valve disorder patients in the intensive care unit: A comprehensive assessment from the MIMIC-III database

BACKGROUND

Mitral valve disorder (MVD) stands as the most prevalent valvular heart disease. Presently, a comprehensive clinical index to predict mortality in MVD remains elusive. The aim of our study is to construct and assess a nomogram for predicting the 28-day mortality risk of MVD patients.

METHODS

Patients diagnosed with MVD were identified via ICD-9 code from the MIMIC-III database. Independent risk factors were identified utilizing the LASSO method and multivariate logistic regression to construct a nomogram model aimed at predicting the 28-day mortality risk. The nomogram's performance was assessed through various metrics including the area under the curve (AUC), calibration curves, Hosmer-Lemeshow test, integrated discriminant improvement (IDI), net reclassification improvement (NRI), and decision curve analysis (DCA).

RESULTS

The study encompassed a total of 2771 patients diagnosed with MVD. Logistic regression analysis identified several independent risk factors: age, anion gap, creatinine, glucose, blood urea nitrogen level (BUN), urine output, systolic blood pressure (SBP), respiratory rate, saturation of peripheral oxygen (SpO2), Glasgow Coma Scale score (GCS), and metastatic cancer. These factors were found to independently influence the 28-day mortality risk among patients with MVD. The calibration curve demonstrated adequate calibration of the nomogram. Furthermore, the nomogram exhibited favorable discrimination in both the training and validation cohorts. The calculations of IDI, NRI, and DCA analyses demonstrate that the nomogram model provides a greater net benefit compared to the Simplified Acute Physiology Score II (SAPSII), Acute Physiology Score III (APSIII), and Sequential Organ Failure Assessment (SOFA) scoring systems.

CONCLUSION

This study successfully identified independent risk factors for 28-day mortality in patients with MVD. Additionally, a nomogram model was developed to predict mortality, offering potential assistance in enhancing the prognosis for MVD patients. It's helpful in persuading patients to receive early interventional catheterization treatment, for example, transcatheter mitral valve replacement (TMVR), transcatheter mitral valve implantation (TMVI).

Heart rate-dependent mitral regurgitation

Mitral regurgitation (MR) is a particularly dynamic valvular disorder. Extreme bradycardia can lead to prolonged left ventricular filling time and mitral annular dilatation, hence causing secondary MR in a structurally normal mitral valve.

Mitral Interventions in Heart Failure

Patients with heart failure with reduced ejection fraction who have secondary mitral regurgitation (SMR) have poorer outcomes and quality of life than those without SMR. Guideline-directed medical therapy is the cornerstone of SMR treatment. Careful evaluation of landmark trials using mitral transcatheter edge-to-edge repair in SMR has led to an improved understanding of who will benefit from percutaneous interventions with emphasis on a multidisciplinary approach. The success with mitral transcatheter edge-to-edge repair in SMR has also spurred the evaluation of its role in populations that were not initially studied, such as end-stage heart failure and cardiogenic shock. A spectrum of transcatheter devices in development and clinical trials promise to further provide a growing array of management options for heart failure with reduced ejection fraction patients with symptomatic SMR.

Mitral Annular Elasticity Determines Severity of Regurgitation in Barlow's Disease

AIMS

Barlow's disease (BD) with late systolic mitral regurgitation provides diagnostic and therapeutic challenges. The mechanisms of the regurgitation are still unclear. We hypothesized that the onset and the severity of late systolic regurgitation are determined by annulus dynamics and the mechanical stresses imposed by the left ventricle.

METHODS AND RESULTS

Ten patients with BD and mitral annulus disjunction (MAD) were compared with ten healthy controls. Resting blood pressure (BP) was measured and transthoracic three-dimensional (3D) echocardiography was analyzed using a holographic display that allows tracking and measurements of mitral annulus surface area (ASA) throughout the cardiac cycle. A novel annulus elastance index (dASA/dP) was calculated between aortic valve opening and onset of mitral regurgitation. Severity of MAD was quantified as the disjunction index (mm*degree). Leaflet coaptation area was calculated using a finite element model. Peak systolic ASA in controls and patients were 9.3±0.6 and 21.1±3.1 cm², respectively (p<0.001). In patients ASA increased rapidly during LV ejection and onset of mitral regurgitation coincided closely with peak upslope of annulus area change (dASA/dt). The finite element model showed a close association between rapid annulus displacement and coaptation area deficit in BD. Systolic annulus elastance index (0.058±0.036 cm²/mmHg) correlated strongly with disjunction index (r=0.91, p<0.0001). Moreover, regurgitation volume showed a positive correlation with systolic BP (r=0.80, p<0.01) CONCLUSION: The present pilot study supports the hypothesis that annulus dilatation may accentuate mitral valve regurgitation in patients with Barlow's disease. A novel annulus elastance index may predict the severity of mitral valve regurgitation in selected patients.

Optimal Management of Chronic Severe Aortic Regurgitation - How to Determine Cutoff Values for Surgical Intervention?

Aortic regurgitation (AR) is a common valvular heart disease, but the optimal timing of surgical intervention remains controversial. In the natural history of chronic severe AR, sudden death is rare, and the annual mortality rate is comparatively low. Considering the hemodynamic features of combined volume and pressure overload and long-term compensation in patients with chronic AR, symptoms related to AR do not frequently occur. Therefore, the progression of left ventricular (LV) dysfunction is a key factor in determining the timing of surgical intervention in patients with severe chronic AR. In addition to symptoms, an ejection fraction <50% and an LV endsystolic diameter (LVESD) >45 mm are appropriate cutoff values for surgical intervention in Japanese patients, whereas LV end-diastolic diameter is not a good indicator. An LVESD index of 25 mm/m²is controversial, because adjusting for body size may cause overcorrection in Japanese patients who have a small body size compared with Westerners. Accumulation of data from the Japanese population is indispensable for establishing guidelines on optimal management of patients with chronic AR.

The advantages, pitfalls and limitations of guideline-directed medical therapy in patients with valvular heart disease

Heart failure is an inevitable end-stage consequence of significant valvular heart disease (VHD) that is left untreated and increasingly encountered in an ageing society. Recent advances in transcatheter procedures and improved outcomes after valve surgery mean that intervention can (and should) be considered in all patients - even the elderly and those with multiple comorbidities - at earlier stages of the natural history of primary VHD, before the onset of irreversible left ventricular dysfunction (and frequently before the onset of symptoms). All patients with known VHD should be monitored carefully in the setting of a heart valve clinic and those who meet guideline criteria for surgical or transcatheter intervention referred for intervention without delay. High quality evidence for the use of medical therapy in VHD is limited and achieving target doses in an elderly and comorbid population frequently challenging. Furthermore, determining whether the valve or ventricle is the principal disease driver is crucial (although the distinction is not always binary, and often unclear). Guideline-directed medical therapy remains the mainstay of treatment for secondary mitral regurgitation - although up to 50% of patients may fail to respond and should be considered for cardiac resynchronization, transcatheter or surgical valve intervention. Early and definitive management strategies are essential and should be overseen by a specialist Heart Team that includes a Heart Failure specialist. In this article, we provide an evidence-based summary of approaches to the medical treatment of VHD and clinical guidance for the best management of patients in situations where high quality evidence is lacking.

Angiotensin-Converting Enzyme Inhibitor Prescription for Patients With Single Ventricle Physiology Enrolled in the NPC-QIC Registry

Background

The routine use of angiotensin‐converting enzyme inhibitors (ACEI) during palliation of hypoplastic left heart syndrome is controversial. We sought to describe ACEI prescription in the interstage between stage 1 palliation (stage I Norwood procedure) discharge and stage 2 palliation (stage II superior cavopulmonary anastomosis procedure) admission using the NPC‐QIC (National Pediatric Cardiology Quality Improvement Collaborative) registry.

Methods and Results

Analysis of all patients (n=2180) enrolled in NPC‐QIC from 2008 to 2016 included preoperative anatomy, risk factors, and echocardiographic data. ACEI were prescribed at stage I Norwood procedure discharge in 38% of patients. ACEI prescription declined from 2011 to 2016 compared with pre‐2010 (36.8% versus 45%; P=0.005) with significant variation across centers (range 7–100%; P<0.001) and decreased prescribing rates associated with increased center volume (P=0.004). There was no difference in interstage mortality (P=0.662), change in atrioventricular valve regurgitation (P=0.101), or change in ventricular dysfunction (P=0.134) between groups. In multivariable analysis of all patients, atrioventricular septal defect (odds ratio [OR], 1.84; 95% CI, 1.28–2.65) or double outlet right ventricle (OR, 1.47; CI, 1.02–2.11), and preoperative mechanical ventilation (OR, 1.37; 95% CI, 1.12–1.68) were associated with increased ACEI prescription. In multivariable analysis of patients with complete echocardiographic data (n=812), ACEI prescription was more common with at least moderate atrioventricular valve regurgitation (OR, 1.88; 95% CI, 1.22–2.31).

Conclusions

ACEI prescription remains common in the interstage despite limited evidence of benefit. ACEI prescription is associated with preoperative mechanical ventilation, double outlet right ventricle, and atrioventricular valve regurgitation with marked inter‐center variation. ACEI prescription is not associated with reduction in mortality, ventricular dysfunction, or atrioventricular valve regurgitation during the interstage.

The Role of Arterial Hypertension in Mitral Valve Regurgitation

PURPOSE OF REVIEW

To review medical literature for evidence of association between hypertension and mitral regurgitation (MR) and summarize potential favorable effects of antihypertensive drugs on MR natural history and treatment.

RECENT FINDINGS

Hypertension and MR are common diseases affecting a large proportion of the general population. Contemporary evidence suggests that hypertension may worsen the progression and prognosis of MR through augmented mechanical stress and increased regurgitation volume. Renin-angiotensin axis inhibitors, beta-blockers, and vasodilators have been tested in order to prevent or decrease primary or secondary MR. Although antihypertensive agents may improve hemodynamic parameters and left ventricular remodeling in primary MR, there is no strong evidence of benefit on clinical outcomes. On the other hand, a beneficial effect of these drugs on secondary MR is better established. Moreover, there are no studies evaluating a possible benefit of lower blood pressure targets in MR. Randomized controlled trials are warranted to elucidate the precise role of antihypertensive therapy on treatment of MR.

Left ventricular remodelling in chronic primary mitral regurgitation: implications for medical therapy

Surgical repair or replacement of the mitral valve is currently the only recommended therapy for severe primary mitral regurgitation. The chronic elevation of wall stress caused by the resulting volume overload leads to structural remodelling of the muscular, vascular and extracellular matrix components of the myocardium. These changes are initially compensatory but in the long term have detrimental effects, which ultimately result in heart failure. Understanding the changes that occur in the myocardium due to volume overload at the molecular and cellular level may lead to medical interventions, which potentially could delay or prevent the adverse left ventricular remodelling associated with primary mitral regurgitation. The pathophysiological changes involved in left ventricular remodelling in response to chronic primary mitral regurgitation and the evidence for potential medical therapy, in particular beta-adrenergic blockers, are the focus of this review.

Comparison of effects of losartan and metoprolol on left ventricular and aortic function at rest and during exercise in chronic aortic regurgitation

Aortic regurgitation (AR) increases the hemodynamic load on both the left ventricle (LV) and the aorta. Vasodilators and beta-blockers both reduce systemic blood pressure, but their relative effects on the LV and aortic function and aortic regurgitant fraction in chronic AR are uncertain. We aimed to compare short-term effects of losartan and metoprolol on LV and aortic function in asymptomatic patients with chronic moderate to severe AR, both at rest and during exercise, using cardiac magnetic resonance (CMR) imaging. 17 chronic AR patients were randomized to 4-6 weeks losartan followed by metoprolol, or vice versa, in a cross-over design. Aortic regurgitant fraction, aortic distensibility, pulse wave velocity and LV function were assessed at rest and after moderate exercise stress (29 ± 7 W, heart rate increase 25 ± 6 bpm) using CMR. Chronic AR patients on metoprolol had a significantly lower mean heart rate, cardiac power index and rate-pressure product, than on losartan (all p < 0.01). However, aortic regurgitant fraction was greater on metoprolol compared to losartan (by 7 ± 11%, p = 0.02). Metoprolol was also associated with a greater reduction in aortic distensibility during exercise than losartan (- 2.4 ± 1.5 × 10^-3 vs - 1.7 ± 2.1 × 10^-3 mmHg^-1 respectively, p = 0.04). End-diastolic volume index was higher on metoprolol than losartan at exercise (difference 6.6 ± 7.8 ml/m², p < 0.01), as was end-systolic volume index (difference 4.0 ± 5.2 ml/m², p < 0.01). Losartan and metoprolol have significantly different short-term effects on aortic regurgitation and LV and aortic function in chronic AR. Further research is required to determine the long-term clinical significance of these changes.

Primary mitral valve regurgitation: Update and review

Mitral regurgitation is the second most common valvular disorder requiring surgical intervention worldwide. This review summarizes the current understanding of primary, degenerative mitral regurgitation with respect to etiology, comprehensive assessment, natural history and management. The new concept of staging of the valvular disorders, newer predictors of adverse and controversy of “watchful waiting” versus “early surgical intervention” for severe, asymptomatic, primary mitral regurgitation are addressed.

Safety and Efficacy of Enalapril in Multivalvular Heart Disease with Significant Mitral Stenosis—SCOPE-MS

Angiotensin-converting enzyme inhibitors (ACEI) are often used in preventing and treating heart failure due to regurgitant valve disease. The majority of patients with symptomatic rheumatic heart disease (RHD) have significant mitral stenosis (MS) and are denied ACEI therapy, because of the fear of hypotension in the presence of fixed obstruction. The authors assessed the safety and efficacy of ACEI in 109 consecutive patients with RHD and with significant mitral stenosis (mitral valve orifice, MVO <1.5 cm2) and with NYHA class III or IV heart failure symptoms. Mean age was 33.1 ±12 years, systolic blood pressure (BP) was 111 ±10, and diastolic BP was 73 ±8 mm Hg. MS was significant in 100 patients with mitral regurgitation in 46, aortic regurgitation in 19, and pulmonary hypertension in 60 patients. After initial stabilization, enalapril 2.5 mg bid was started in hospital and titrated up to 10 mg bid over 2 weeks. NYHA status, Borg score, and 6-minute walk test were assessed at baseline, and at 1, 2, and 4 weeks. Seventy-nine of the 100 patients who completed the study had severe MS (MVO <1.0 cm2). Enalapril was well tolerated by all study patients without hypotension or worsening of symptoms. NYHA class (3.2 ±0.5 baseline vs 2.3 ±0.5 at 4 weeks, p<0.01) Borg Dyspnea Index (7.6 ±1.3 vs 5.6 ±1.3, p<0.01), and 6-minute walk distance (226 ±106 vs 299 ±127 m, p<0.01) improved significantly with enalapril. Patients with associated regurgitant lesions showed more improvement in exercise capacity (120 ±93 vs 39 ±56 m, p<0.001). Enalapril was well tolerated in patients with RHD with moderate and severe MS. Irrespective of the valve pathology, enalapril improved functional status and exercise capacity with maximum benefit in patients with concomitant regurgitant valvular heart disease.

Effects of early and late-onset treatment with carvedilol in an experimental model of aortic regurgitation

Background

Beta-blockade is contraindicated in severe aortic regurgitation (AR) due to the fear of prolonging diastole and thus aggravate regurgitation. However, this has never been scientifically proven and positive effects of targeting the sympathetic system in AR has been demonstrated in several studies.

Method

Thirty-nine Sprague–Dawley rats with AR were randomized to ten weeks of medical treatment with carvedilol or no treatment. Treatment was initiated either early or late after AR induction. The effect of carvedilol was assessed by serial echocardiography and invasive hemodynamic measurements.

Results

AR resulted in eccentric hypertrophy and left ventricular (LV) dysfunction. LV remodeling and function as measured by echocardiography was unaffected by treatment. LV dimensions were similar between treated and untreated groups and measures of LV performance (including strain and strain rate) were also unaltered. This result was confirmed by invasive measurements showing maximal and minimal pressure–time development, LV volumes, and LV pressures, to be unaltered by treatment. On the contrary, despite relative bradycardia carvedilol did not reflect any negative impact on the heart.

Conclusion

Carvedilol did not improve left ventricular remodeling or function in rats with surgically induced AR. Despite relative bradycardia, we did not find carvedilol to negatively impact the heart, either when treatment was initiated early or late in the course of disease.

Percutaneous mitral repair with the MitraClip system in patients with mild-to-moderate and severe heart failure: a single-centre experience

AIMS

Edge-to-edge repair of mitral regurgitation (MR) with the MitraClip(®) (MC) system is increasingly applied in advanced heart failure. Our objective was to compare outcomes in patients with mild-to-moderate and severe systolic heart failure.

METHODS AND RESULTS

Between February 2010 and July 2012, 121 patients with MR of at least grade 3+ and a mean EuroSCORE II of 10.6% underwent MC implantation. Thirty-nine had a left ventricular ejection fraction (LVEF) of ≤30% (group A) and 82 of >30% (group B). Procedural success was comparable in both groups (100% vs. 95.2%) with multiple (>2) clip implantation in 34% and 25% of patients, respectively. At 12 months, absolute reduction in MR grade (2.3 vs. 2.2) and relative reduction in mitral valve orifice area (48% vs. 42%) were also comparable. New York Heart Association class had improved independent from baseline LVEF (P < 0.001). In-hospital mortality was low in both groups (2.6% vs. 2.4%), but there was a strong trend for higher 12-month mortality in group A (34% vs. 18%, P = 0.05) with no significant difference in the overall rate of major adverse cerebrovascular and cardiac events (36.8% vs. 28.9%, P = 0.38). On multivariate analysis, MR grade after repair was the strongest predictor of mortality (OR 2.121, 95% CI 1.095-4.109), whereas systolic impairment was no independent predictor.

CONCLUSIONS

Percutaneous mitral valve repair led to comparable symptomatic improvement in patients with mild-to-moderately or severely reduced LV function. LV-EF < 30% was not an independent predictor of short-term mortality, which was mainly governed by residual MR after repair.

Chronic vagus nerve stimulation improves left ventricular function in a canine model of chronic mitral regurgitation

BACKGROUND

Autonomic dysfunction, characterized by sympathetic activation and vagal withdrawal, contributes to the progression of heart failure (HF). We hypothesized that chronic vagus nerve stimulation (VNS) could prevent left ventricular (LV) remodeling and dysfunction in a canine HF model induced by chronic mitral regurgitation (MR).

METHODS AND RESULTS

After the MR inducing procedure, 12 survived canines were randomly divided into the control (n = 6) and the VNS (n = 6) groups. At month 2, a VNS stimulator system was implanted in all canines. From month 3 to month 6, VNS therapy was applied in the VNS group but not in the control group. At month 6, compared with the control group, the canines in VNS group had significantly higher cardiac output (2.3 ± 0.3 versus 2.9 ± 0.4 L/min, P < 0.05, LV forward stroke volume (20.1 ± 3.7 versus 24.8 ± 3.9 ml, P < 0.05), and end-systolic stiffness constant (2.2 ± 0.3 versus 2.7 ± 0.3, P < 0.05). NT-proBNP and C-reactive protein were decreased significantly in the VNS group. However, no statistical difference was found in LV ejection fraction, LV end-diastolic dimension, LV end-diastolic volume, myocyte cross-sectional area, or collagen volume fraction between two groups.

CONCLUSIONS

Chronic VNS therapy may ameliorate MR-induced LV contractile dysfunction and improve the expression of biomarkers, but has less effect in improving LV chamber remodeling.

How to grade mitral regurgitation: an integrative approach

Evaluation of mitral regurgitation (MR) severity remains complex and challenging. An integrative approach to grading MR is recommended. The use of multiple Doppler methods should be used to help discriminate between grades of severity. Importantly, MR severity should always be considered in the context of clinical data. The emerging inclusion of 3-dimensional echocardiography may provide complementary data for MR quantification and better anatomic and pathophysiological detail of the mitral valve. This article summarizes recommendations for MR assessment and highlights the importance of an integrated approach, using anatomic information as well as qualitative and quantitative Doppler measures.

The novel mitochondrial 16S rRNA 2336T>C mutation is associated with hypertrophic cardiomyopathy

Background

Hypertrophic cardiomyopathy (HCM) is a primary disorder characterised by asymmetric thickening of septum and left ventricular wall, with a prevalence of 0.2% in the general population.

Objective

To describe a novel mitochondrial DNA mutation and its association with the pathogenesis of HCM.

Methods and results

All maternal members of a Chinese family with maternally transmitted HCM exhibited variable severity and age at onset, and were implanted permanent pacemakers due to complete atrioventricular block (AVB). Nuclear gene screening (MYH7, MYBPC3, TNNT2 and TNNI3) was performed, and no potential pathogenic mutation was identified. Mitochondrial DNA sequencing analysis identified a novel homoplasmic 16S rRNA 2336T>C mutation. This mutation was exclusively present in maternal members and absent in non-maternal members. Conservation index by comparison to 16 other vertebrates was 94.1%. This mutation disturbs the 2336U-A2438 base pair in the stem–loop structure of 16S rRNA domain III, which is involved in the assembly of mitochondrial ribosome. Oxygen consumption rate of the lymphoblastoid cells carrying 2336T>C mutation had decreased by 37% compared with controls. A reduction in mitochondrial ATP synthesis and an increase in reactive oxidative species production were also observed. Electron microscopic analysis indicated elongated mitochondria and abnormal mitochondrial cristae shape in mutant cells.

Conclusions

It is suggested that the 2336T>C mutation is one of pathogenic mutations of HCM. This is the first report of mitochondrial 16S rRNA 2336T>C mutation and an association with maternally inherited HCM combined with AVB. Our findings provide a new insight into the pathogenesis of HCM.

Echocardiographic assessment of mitral regurgitation: general considerations

Echocardiography is undoubtedly one of the main tools used in assessment of mitral regurgitation (MR) because it allows characterization of valvular morphology, assessment of the severity of the regurgitation, and its secondary effects. In this article we present an overview of the echocardiographic assessment of MR.

Medical treatment of asymptomatic chronic aortic regurgitation

Chronic aortic regurgitation results in left ventricular (LV) dilation, increased LV work and, eventually, a decline in LV function and heart failure. An important question is whether pharmacological therapy could preserve LV function and delay the need for aortic valve replacement. Vasodilators have a number of theoretical advantages. By lowering blood pressure, they reduce the regurgitant volume and decrease LV afterload. This article summarizes the clinical studies that have evaluated vasodilators in asymptomatic patients with chronic aortic regurgitation. Some studies suggest favorable effects on LV function and clinical outcomes, but results are inconsistent, making it difficult to draw definite conclusions. In general, studies have been too small to reliably evaluate the overall benefits and risks of this treatment, and in several studies there was no significant difference in measured blood pressure by treatment allocation. For these reasons, decisions on whether vasodilators are indicated in individual patients must currently be based on clinical judgment alone.

MitraClip® therapy in patients with end-stage systolic heart failure

AIMS

To assess the feasibility, short-term durability and clinical outcomes of MitraClip® therapy for mitral regurgitation (MR) in patients with end-stage heart failure and a severely reduced left ventricular (LV) ejection fraction.

METHODS AND RESULTS

We analysed retrospectively collected data from seven European centres. Included in the study were 50 heart failure patients [mean age 70 ± 11 years, 38 men (76%)] with a LV ejection fraction ≤25% and MR of at least grade 3+. All patients had functional MR, were in New York Heart Association (NYHA) functional class III or IV, and their mean logistic EuroSCORE was 34%. The patients underwent a total of 53 MitraClip® procedures; one or more clips were implanted in 50 procedures (48 patients), for an acute procedural success rate of 94%. Severity of MR was reduced in all successfully treated patients, 44 (92%) were discharged with MR ≤2+. Thirty-day mortality was 6%; cumulative survival at 6 months was 81.2%. Clinical and echocardiographic 6-month follow-up data were obtained from 32 and 31 successfully treated patients, respectively. At 6 months, MR ≤2+ was present in 27 (87%) of 31 patients, and 23 (72%) of 32 patients were in NYHA functional class I or II. Six-minute walk distance improved significantly, and significant reductions in LV volumes indicative of reverse LV remodelling were concordant with significant reductions in N-terminal pro-brain natriuretic peptide plasma levels.

CONCLUSION

MitraClip® therapy reduces functional MR in patients with end-stage heart failure and marked LV dysfunction and entails clinical benefit at 6 months.

Acute outcomes of MitraClip therapy for mitral regurgitation in high-surgical-risk patients: emphasis on adverse valve morphology and severe left ventricular dysfunction

AIMS

We sought to assess the feasibility of catheter-based mitral valve repair using the MitraClip system in high-surgical-risk patients with mitral regurgitation (MR) > or =grade 3+.

METHODS AND RESULTS

MitraClip therapy was performed in 51 consecutive patients [73 +/- 10 years; 34 (67%) men] with symptomatic functional [n = 35 (69%)] or organic MR [n = 16 (31%)]. Mean logistic EuroSCORE was 29 +/- 22%; Society of Thoracic Surgeons score was 15 +/- 11. Left ventricular (LV) ejection fraction was 36 +/- 17%. In 35 patients (69%), adverse mitral valve morphology and/or severe LV dysfunction were present. MitraClip implantation was successful in 49 patients (96%). Most patients [n = 34/49 (69%)] were treated with a single clip, whereas 14 patients (29%) received two clips and one patient received three clips. Mean device and fluoroscopy times were 105 +/- 65 min and 44 +/- 28 min, respectively. Procedure-related reduction in MR severity was one grade in 16 patients (31%), two grades in 24 patients (47%), and three grades in 9 patients (18%). Forty-four of the 49 successfully treated patients (90%) showed clinical improvement at discharge [NYHA functional class > or =III in 48 patients (98%) before and 16 patients (33%) after the procedure (P < 0.0001)]. There were no procedure-related major adverse events and no in-hospital mortality.

CONCLUSION

Mitral valve repair using the MitraClip system was shown to be feasible in patients at high surgical risk primarily determined by an adverse mitral valve morphology and/or severe LV dysfunction.

[Moderate ischemic mitral regurgitation: to operate or to ignore?]

INTRODUCTION

Moderate ischemic mitral regurgitation (MR) is characterized by significant, symptomatic multivessel coronary disease and mitral regurgitation 2-3+.

CASE OUTLINE

A 60-year-old patient was admitted at the Cardiovascular Institute "Dedinje" due to the symptoms of unstable angina pectoris. He survived a myocardial infarction (inferoposterolateral localization) 8 years ago. On admission echocardiogram revealed regional disturbances of the left ventricle wall with ejection fraction of 25% and mitral regurgitation 2+. The patient underwent a triple coronary bypass with surgical correction of mitral regurgitation. Postoperative course was normal.

CONCLUSION

Several authors are against surgical correction of MR in moderate ischemic MR due to several reasons: revascularization of ischemic areas will improve regional wall motion and correct MR, while mitral valve surgery adds significantly to the operative risk of coronary surgery. Other authors, however, favour combined operation emphasizing that in many patients coronary surgery alone will not correct a moderate ischemic MR. Today there is no consensus whether to operate the moderate ischemic MR or to ignore it. Some novel studies underscore significant predictors of a long-term survival of these patients: NYHA (New York Heart Association) class and left ventricle ejection fraction. In that respect a combined operation should be recommended in patients with heart failure and NYHA class III and IV.

Mitral regurgitation

Mitral regurgitation affects more than 2 million people in the USA. The main causes are classified as degenerative (with valve prolapse) and ischaemic (ie, due to consequences of coronary disease) in developed countries, or rheumatic (in developing countries). This disorder generally progresses insidiously, because the heart compensates for increasing regurgitant volume by left-atrial enlargement, causes left-ventricular overload and dysfunction, and yields poor outcome when it becomes severe. Doppler-echocardiographic methods can be used to quantify the severity of mitral regurgitation. Yearly mortality rates with medical treatment in patients aged 50 years or older are about 3% for moderate organic regurgitation and about 6% for severe organic regurgitation. Surgery is the only treatment proven to improve symptoms and prevent heart failure. Valve repair improves outcome compared with valve replacement and reduces mortality of patient with severe organic mitral regurgitation by about 70%. The best short-term and long-term results are obtained in asymptomatic patients operated on in advanced repair centres with low operative mortality (<1%) and high repair rates (>/=80-90%). These results emphasise the importance of early detection and assessment of mitral regurgitation.

Effectiveness of angiotensin-converting enzyme inhibitors in pediatric patients with mid to severe aortic valve regurgitation

The long-term benefit of angiotensin-converting enzyme inhibitors in pediatric patients with aortic valve regurgitation is under consideration. Eighteen patients with mid to severe aortic valve regurgitation were retrospectively evaluated. Echocardiographic parameters (left ventricular end-diastolic diameter, shortening fraction, left ventricular posterior wall thickness, and grade of aortic valve regurgitation) were analyzed before and during therapy with angiotensin-converting enzyme inhibitors. Data are given as standard deviation scores (Z-scores) derived from body surface-adjusted normal values. Median (interquartile range) age at start of therapy was 8.4 (5.4 to 10.0) years, and total follow-up 2.3 (0.9 to 5.4) years. Left ventricular end-diastolic diameter increased from 3.6 (2.3 to 4.5) to 3.7 (2.4 to 4.8), and left ventricular posterior wall diameter decreased from 1.9 (1.1 to 3.0) to 1.1 (0.5 to 2.3). Grade of aortic valve regurgitation increased from 3.5 (2.3 to 4.0) to 4.0 (2.0 to 4.0), and shortening fraction decreased from 39% (34% to 43%) to 37% (34% to 42%). No significant effect of angiotensin-converting enzyme inhibitors on left ventricular dimensions or function was found in our population of patients with mid to severe aortic valve regurgitation. Angiotensin-converting enzyme inhibitors may not alter left ventricular overload in pediatric patients with aortic valve regurgitation.

[Ischemic mitral regurgitation: contributions of exercise echocardiography and new therapeutic perspectives]

The ischemic mitral regurgitation is defined by a left ventricular muscle disease affecting the function of normal mitral valve leaflets. This kind of mitral regurgitation is founded in about 20% of the ischemic cardiomyopathy and is attributed to the remodelling of the left ventricular shape. Its development is associated to a significantly worse prognosis. Frequently this ischemic mitral regurgitation will be associated to episode of acute heart failure decompensation. Its diagnosis is sometimes challenging as the degree of regurgitation might be extremely variable and affected by loading conditions. Echocardiography and especially exercise stress echocardiography has been demonstrated as an extremely powerful tool for its diagnosis and the prognostic evaluation. Its treatment should include the pharmacological treatment of the chonic heart failure and we are still waiting data in regard to the prognostic role of surgical mitral valvuloplastie. Works are still ongoing.

Approach to patients with heart failure and pulmonary hypertension

Pulmonary hypertension (PH), defined as a mean pulmonary artery pressure greater than 25 mm Hg, is not a diagnosis, but rather the physiologic consequence of the interaction between pulmonary blood flow, pulmonary vascular impedance, and downstream pulmonary venous pressure. The diagnosis and appropriate treatment of PH in patients with or without heart failure (HF) requires an understanding of the underlying pathogenesis, whether it be due to increased pulmonary venous pressure, increased pulmonary vascular resistance (PVR), increased pulmonary blood flow, or a combination thereof. Furthermore, an explanation for the underlying cause must also be sought. For example, a rise in pulmonary venous pressure may relate primarily to an increase in left ventricular end-diastolic pressure in a patient with a known cardiomyopathy; however, it may be complicated by severe mitral regurgitation. Similarly, an increased PVR may reflect reactive changes in the pulmonary vasculature due to long-standing pulmonary venous hypertension, concomitant hypoxemia/hypercapnia, or it may be the harbinger of chronic thromboembolic disease. It is imperative that reversible causes of PH be considered. Although most often diagnosed by Doppler echocardiography, full hemodynamic characterization of PH requires right heart catheterization to measure biventricular filling pressures and PVR. Integration of invasive pulmonary hemodynamics with an assessment of right ventricular function is essential to appreciate the clinical and prognostic significance of PH of an individual patient. Right heart catheterization is not practically feasible in all patients with HF and PH; however, at a minimum it should be performed in patients with a Doppler-estimated pulmonary artery pressure greater than 60 mm Hg, those who present clinically with predominant right HF, significant mitral valve disease, and in particular, patients with impaired right ventricular function.

Annular-to-leaflet mismatch and the need for reductive annuloplasty in patients undergoing mitral repair for chronic mitral regurgitation due to mitral valve prolapse

Annular dilation is a common feature of chronic degenerative mitral regurgitation caused by leaflet prolapse. Accordingly, patients undergoing surgical repair usually undergo concomitant reductive annuloplasty to restore a normal annular-to-leaflet relation. With the evolution of transcatheter valve repair technologies, patient selection criteria for those who do not require annuloplasty are needed. A series of patients undergoing mitral repair was analyzed, and the role of annular-to-leaflet mismatch in identifying patients requiring reductive annuloplasty was explored. Preoperative data for 82 patients undergoing mitral repair with annuloplasty for degenerative mitral regurgitation were prospectively collected, including annular intercommissural (IC) and septolateral (SL) dimensions and heights of anterior (ALH) and posterior leaflets. An SL/ALH ratio >1.4 was used to define annular-to-leaflet mismatch. After mitral repair, the ratio between preoperative IC distance and the size of the implanted annular prosthesis (Seguin ring [SR], IC/SR <1.2) was used to identify patients for whom annuloplasty was nonreductive. All patients underwent successful mitral repair. Mean preoperative IC was 46 +/- 6 mm, SL was 42 +/- 5 mm, and ALH was 31 +/- 5 mm. Mean SR was 34 +/- 3 mm, with a mean IC/SR ratio of 1.34 +/- 0.14. Sixteen patients (19%) had an IC/SR ratio <1.2. IC/SR ratio <1.2 was predicted by a SL/ALH ratio < or =1.4 (p = 0.009). In conclusion, annular dilation is negligible in <20% of surgical candidates. In this subgroup, an isolated leaflet repair may be indicated. SL/ALH ratio is a good indicator of annular-to-leaflet mismatch and could be used as an adjunct to other methods of annular function assessment to select patients for ringless mitral repair.

Role of vasodilators in regurgitant valve disease

Vasodilator therapy is designed to reduce regurgitant volume and improve left ventricular function. Acute administration reduces vascular resistance and decreases regurgitant volume and left ventricular filling pressure. These effects may be clinically useful in acute regurgitations, but less consistent results have been reported in long-term therapy. In chronic mitral functional regurgitation, vasodilator therapy has proved to have clinical or prognostic benefit only when heart failure or poor ventricular function is present. The indication of vasodilator treatment in aortic regurgitation has raised significant controversy. Several studies with small series have shown beneficial effects on regurgitant volume, ejection fraction, and mass of the left ventricle. Nevertheless, in the only two randomized long-term follow-up studies, results differed completely. In our experience, both nifedipine and enalapril failed to reduce the need for valvular surgery or show benefits in echocardiographic parameters. Vasodilator therapy would be indicated only in patients with severe aortic regurgitation and systemic hypertension, or when surgery is contraindicated.

Valvular heart diseases

Patients who have valvular heart disease coming for surgery present many challenges to the anesthesiologist. Over the past 3 decades there has been a persistent improvement in our understanding of the pathophysiology of valvular heart disease and in the surgical techniques for correcting it. With the development of efficient and safe noninvasive monitoring of cardiac function, new surgical techniques, better designs of prosthetic valves, and the development of useful guidelines for choosing the proper timing of surgical intervention, patients who have valvular disease with varying physiology can be encountered in the perioperative period. The perioperative physician has to be aware of the varying effects of hemodynamic variables on this subpopulation of patients.