Degenerative Mitral Valve Research Articles

Natural history of coexistent tricuspid regurgitation in patients with degenerative mitral valve disease: Implications for future guidelines

The management of coexistent tricuspid regurgitation in patients with mitral regurgitation remains controversial. We sought to define the incidence and natural history of coexistent tricuspid regurgitation in patients undergoing isolated mitral surgery for degenerative mitral regurgitation, as well as the effect of late secondary tricuspid regurgitation on cardiovascular symptom burden and survival. To minimize confounding, analysis was limited to 495 consecutive patients who underwent isolated mitral surgery for degenerative mitral valve disease between 2002 and 2011. Patients with coexistent severe tricuspid regurgitation were excluded because such patients typically undergo concomitant tricuspid intervention. Grade 1 to 3 coexistent tricuspid regurgitation was present in 215 patients (43%) preoperatively. Actuarial freedom from grade 3 to 4 tricuspid regurgitation 1, 5, and 9 years after surgery was 100% ± 0%, 90% ± 2%, and 64% ± 7%, respectively. Older age (P < .001) and grade of preoperative tricuspid regurgitation (P = .006) independently predicted postoperative progression of tricuspid regurgitation on multivariable analysis. However, when limited to patients with mild or absent tricuspid regurgitation, indexed tricuspid annular diameter was the only significant risk factor for late tricuspid regurgitation (P = .04). New York Heart Association functional class and long-term survival did not worsen with development of late secondary tricuspid regurgitation (P = .4 and P = .6, respectively). However, right ventricular dysfunction was significantly more common in patients with more severe late tricuspid regurgitation (P = .007). Despite durable correction of degenerative mitral regurgitation, less than severe tricuspid regurgitation is likely to progress after surgery if uncorrected. Given the low incremental risk of tricuspid annuloplasty, a more aggressive strategy of concomitant tricuspid repair may be warranted.

Systolic anterior motion of the mitral valve: A 30-year perspective

Systolic anterior motion (SAM) can occur after mitral valve repair (MVr), most frequently in patients with degenerative valve disease. Our initial observations (1981-1990) revealed that most patients with SAM can be successfully treated medically. Here the authors review the last 16 years of their experience with SAM after MVr. Between January 1996 and October 2011, 1918 patients with degenerative mitral valve disease underwent MVr at our institution. We performed a retrospective analysis of SAM in this patient population. The incidence of SAM was 4.6% (89 of 1918) overall, 4.0% (77 of 1906) in patients who did not have SAM preoperatively (de novo). Compared with our previously published report, the incidence of SAM decreased from 6.4% to 4.0% (P = .03). Hospital mortality was 2.0% (38 of 1918) overall, 1.3% (14 of 1078) for isolated MVr. One patient with de novo SAM (1 of 77; 1.3%) died after emergency MVr. All patients with de novo SAM were successfully managed conservatively with intravenous fluids, α agonists, and/or β blockers. A higher incidence of SAM was associated with a left ventricular ejection fraction greater than 60% (P = .01), posterior leaflet resection (P = .048), and hypertrophic obstructive cardiomyopathy (P < .01). The incidence of SAM was lower in patients who underwent device mitral annuloplasty with a semirigid posterior band compared with a complete ring (P = .03). In the more recent era, SAM occurs one-third less frequently after repair of degenerative mitral valve disease. Use of an incomplete annuloplasty band rather than a complete ring is associated with a lower incidence of SAM. The mainstay treatment of SAM continues to be medical management.

Left ventricular dysfunction after mitral valve repair—the fallacy of “normal” preoperative myocardial function

A proportion of patients experience a decrease in left ventricular (LV) ejection fraction (EF) after mitral valve repair; however, predictors and long-term consequences remain unclear. A study of 1705 patients with severe, degenerative mitral valve regurgitation and normal preoperative EF (>60%) undergoing mitral valve repair from 1993 to 2012 was performed. Multivariate logistic regression and Cox proportional hazards models were used to determine the predictors of early postoperative LV dysfunction (EF < 50%) and long-term survival, respectively. Postoperative outcomes were comparable between patients; however, those with an EF of <50% (n = 314, 18.4%) had significantly greater enlargement in systolic dimension (left ventricular end-systolic diameter, -0.6 vs 4.3 mm; P < .001) and decrease in right ventricular systolic pressure (-2.7 vs -7.8 mm Hg; P < .001) immediately after repair. On longitudinal follow-up, early LV impairment persisted, with EF recovering to preoperative levels (>60%) in only one third of patients with postrepair EF <50% versus two thirds of those with an EF of ≥ 50% (P < .001). The overall survival at 5, 10, and 15 years of follow-up was 95%, 85%, and 70.8%, respectively. Although early postoperative EF < 50% was not a significant determinant of late survival, when adjusting for older age (hazard ratio [HR], 1.09), hypertension (HR, 1.38), New York Heart Association class III or IV (HR, 1.71), and preoperative atrial fibrillation (HR, 2.33), postoperative EF < 40% conferred a 70% increase in the hazard of late death (HR, 1.74; 95% confidence interval, 1.03-2.92; P = .037). A preoperative right ventricular systolic pressure >49 mm Hg and left ventricular end-systolic diameter >36 mm were independently associated with a 4.4- and 6.5-fold increased risk of developing a postoperative EF < 40% (P < .001, for both). De novo postoperative LV dysfunction is not uncommon in patients with "normal" preoperative EF undergoing mitral valve repair. LV dysfunction can persist, impairing recovery of LV size, function, and survival. The consideration of mitral repair before the onset of excessive LV dilation or pulmonary hypertension, even in those with preserved EF, seems warranted.

Long-Term Outcomes of Mitral Valve Repair in Degenerative Valve Disease: Comparison Between Posterior and Anterior or Bileaflet Mitral Valve Prolapse

Objective: The aim of this study is to compare the clinical and echocardiographic outcome of mitral valve repair secondary todegenerative mitral valve regurgitation in patients with posterior versus anterior or bileaflet mitral valve prolapse.Methods: Between April 1997 and July 2013, 255 patients underwent surgery for moderate to severe degenerative mitral valveregurgitation: 175 had posterior mitral valve prolapse (Group 1) and 80 had anterior or bileaflet mitral valve prolapse (Group2). There were no differences in age or sex between the groups. Clinical follow-up was completed in 95% of the cases witha mean follow-up period of 5.6 ± 3.8 years and 77% completed echocardiographic follow-up with a mean of 4.8 ± 3.7 years.Results: The procedure was successful in 87% of cases (33 intraoperative conversions to mitral valve replacement) (Group1: 98% vs. Group 2: 62.5%; p < 0.01). Overall in-hospital mortality was 2.3% (6/255), and 10-year survival was 92.0 ± 2.1%(Group 1: 94.4% ± 2.2% vs. Group 2: 86.3 ± 5.1%; p = 0.036). At 10-year follow-up, 95.6 ± 1.6% of patients were free fromreoperation (Group 1: 97.1 ± 1.4% vs. Group 2: 89.7 ± 5.0%; p = 0.035), 79.0 ± 4.4% remained free from moderate to severemitral regurgitation (Group 1: 80.8 ± 4.8% vs. Group 2: 71.9 ± 9.6%; p = 0.14) and 91.2% were asymptomatic (92% Group1 vs. 89.3% Group 2; p = 0.5).Conclusions: Patients undergoing mitral valve repair secondary to degenerative posterior mitral valve prolapse had highersurvival and lower incidence or reoperation in the long-term follow-up. There were no differences in freedom from moderateto severe mitral regurgitation between both groups at 10-year follow-up.

A simple approach to mitral valve repair: Posterior leaflet height adjustment using a partial fold of the free edge

Multiple techniques have been used to repair degenerative mitral valve prolapse with leaflet elongation, without creating systolic anterior motion. We describe a simple, reproducible, measured technique to guide repair. From January 2010 to July 2012, 171 patients underwent mitral valve repair; 128 (75%) with Carpentier type II prolapse. For 48 patients (37.5%), the resected posterior leaflet free edge was partially folded to restore the normal 2:1 ratio of the A2 and P2. All patients underwent complete ring annuloplasty sized to the height of A2. The preoperative A2/P2 ratio was 1.5 ± 0.5. After repair, the A2/P2 ratio was 1.9 ± 0.3 and 2.0 ± 0.3 in the no fold and partial fold groups, respectively (P = .57). The ring sizes were larger in the partial fold group (P < .001) because the A2 height was larger (P = .001). No obstructive systolic anterior motion was present. Of the 171 patients, 91.4% had grade 4+ preoperative mitral regurgitation, with no 3 or 4+ mitral regurgitation during follow-up. At the last follow-up visit, grade 2+ mitral regurgitation was observed in 5% of the patients. No 30-day mortalities or reoperations occurred. Partial fold of the posterior leaflet free edge is a simple technique to restore the normal 2:1 ratio of A2/P2 with a ring size determined by the A2 height. Using just the A2 height, mitral surgeons can reproducibly repair the posterior leaflet prolapse, choose the appropriate ring size, and avoid more complex leaflet reconstruction or judgment of the neochord length.

Value of robotically assisted surgery for mitral valve disease.

The value of robotically assisted surgery for mitral valve disease is questioned because the high cost of care associated with robotic technology may outweigh its clinical benefits. To investigate conditions under which benefits of robotically assisted surgery mitigate high technology costs. Clinical cohort study at a large multispecialty academic medical center comparing costs of robotically assisted surgery with 3 contemporaneous conventional surgical approaches for degenerative mitral valve disease. From January 1, 2006, through December 31, 2010, a total of 1290 patients with a mean (SD) age of 57 (11) years underwent mitral valve repair for regurgitation from posterior leaflet prolapse. Robotically assisted surgery was performed in 473 patients, complete sternotomy in 227, partial sternotomy in 349, and anterolateral thoracotomy in 241. Comparisons were based on intent to treat, with 3 propensity-matched groups formed based on demographics, symptoms, cardiac and noncardiac comorbidities, valve pathophysiologic disorders, and echocardiographic measurements: robotic vs sternotomy (198 pairs) vs partial sternotomy (293 pairs) vs thoracotomy (224 pairs). Mitral valve repair. Cost of care (expressed as robotic capital investment, maintenance of equipment, and direct technical hospital costs) and benefit of care (based on differences in recovery time). Cost of care (median [15th and 85th percentiles]) for robotically assisted surgery exceeded that of alternative approaches by 26.8% (-5.3% and 67.9%), 32.1% (-6.1% and 69.6%), and 20.7% (-2.4% and 48.4%) for complete sternotomy, partial sternotomy, and anterolateral thoracotomy, respectively. Higher operative costs were partially offset by lower postoperative costs and earlier return to work: a median (15th and 85th percentiles) of 35 (19 and 63) days for robotically assisted surgery, 49 (21 and 109) days for complete sternotomy, 56 (30 and 119) days for partial sternotomy, and 42 (18 and 90) days for anterolateral thoracotomy. Resulting net differences (median [15th and 85th percentiles]) in the cost of robotic surgery vs the 3 alternatives were 15.6% (-14.7% and 55.1%), 15.7% (-19.4% and 51.2%), and 14.8% (-7.4% and 43.6%), respectively. Beyond a volume threshold of 55 to 100 robotically assisted operations per year, distribution of the cost of this technology broadly overlapped those of conventional approaches. In exchange for higher procedural costs, robotically assisted surgery for mitral valve repair offers the clinical benefit of least-invasive surgery, lowest postoperative cost, and fastest return to work. The value of robotically assisted surgery that is similar to that of conventional approaches can be realized only in high-volume centers.

Evaluation Of Mid-Term Clinical And Echocardiographic Outcomes Of Alfieri (Edge-To-Edge) Mitral Valve Repair

Aim: The present study aimed to evaluate mid-term clinical and echocardiographic outcomesof the Alfieri edge-to-edge repair performed on patients with moderate to severe mitralregurgitation (MR).Methods: Thirty patients (mean age, 61.2±11.2 years; 18 males) with moderate to severe MRof different etiologies and a pulmonary artery pressure (PAP) of >40 mmHg who underwent aAlfieri repair between 2005 and 2011 were included. All patients were selected and followed bythe same surgical team and cardiologist. The Alfieri edge-to-edge repair with ring annuloplastywas performed. The patients were postoperatively evaluated in terms of degree of MR, functionalcapacity according to the New York Heart Association (NYHA) classification, PAP, left atrialdiameter (LAD), atrial fibrillation, ejection fraction (EF), risk of functional mitral stenosis,etiological factors, and mortality.Results: Postoperative NYHA class, MR and LAD values of the study patients were significantlybetter as compared to the preoperative values (p<0.001). The rate of patients with increasedmean PAP in the preoperative period significantly reduced in the postoperative period (70% vs.30%, p<0.001). Functional mitral stenosis developed in only one patient. Mortality was foundhigher in the patients with ischemic MR with higher NYHA functional class than in those withdegenerative or rheumatic MR.Conclusion: Mid-term outcomes of the Alfieri edge-to-edge repair with ring annuloplasty,particularly in degenerative mitral valve pathologies, are promising. Regression in symptoms,improvements in functional capacity and examination findings, and decrease in the degree ofMR, and the improvements in the echocardiographic findings including decrease in PAP andLAD values, and the absence of atrial fibrillation and thromboembolism are important clinicaloutcomes

Heart rate variability and arrhythmias evaluated with Holter in dogs with degenerative mitral valve disease

Cardiac diseases promote alterations in the autonomic control of the heart, leading to an increase in heart rate and, as a result, a decrease in heart rate variability (HRV).The aim of this study was to evaluate if the development of heart failure secondary to degenerative mitral valve disease (DMVD) concurs with changes in autonomic modulation of heart rhythm which are assessed by long electrocardiography examination (Holter). Dogs were evaluated by clinical examination and echocardiography in order to be categorized into the following groups: Control (healthy; n=6), DMVD (disease without heart failure; n=8), and DMVD heart failure (disease with heart failure; n=13). Arrhythmias and frequency domain HRV were determined by Holter. Diseased animals, when compared to healthy, had significantly lower total power, which indicates overall HRV. DMVD heart failure dogs also showed other disturbances such as high incidence of supraventricular arrhythmias, high heart rate, little amount of pauses (2.0s long between consecutive heartbeats), longer time in tachycardia, shorter time in bradycardia, low high frequency (parasympathetic control), and high low frequency (sympathetic and parasympathetic control) when compared to control (p&lt;0.05). In DMVD dogs, Holter-derived variables changed with the development of heart failure.

Advanced degenerative mitral valve disease and congestive heart failure in dogs

Degenerative mitral valve disease (DMVD) is the most common cardiovascular disease in dogs and is a major cause of congestive heart failure (CHF) in this species. This article reviews the pathophysiology and natural history of the disease and provides a summary of current recommendations for diagnosis and treatment of dogs with advanced DMVD and CHF.

0235: Contribution of endothelial cells, serotonergic 5-HT2A and 5-HT2B receptors and eNOS in early processes of valve degeneration due to nordexfenfluramine in mice

Chronic use of 5-HT 2B receptor (5-HT 2B -R) agonists (anorectic drugs or ergot derivatives) has been associated with left cardiac valve injury but the mechanisms are unclear. Lesions are characterised by increased thickness and cellularity with massive extracellular matrix production. This work was designed to study contribution of 5-HT 2B and 5-HT 2A -R and the link with their activation and endothelial nitric oxide in valve degeneration. We validated an experimental mouse model of valvulopathy by infusing (28 days; Alzet ® pumps) the selective 5-HT 2B -R agonist (nordexfenfluramine: NdF 1 mg/kg/day) and designed 13 groups: 5 groups of WT mice (129svPas; 12 weeks): 1) control (C); 2) NdF; 3) NdF+ritanserine (2 mg/kg/day); 4) NdF+SB206553 (1 mg/kg/day); 5) NdF+LNAME (300 mg/kg/day); 8 groups of transgenics: 6) 5-HT 2B -/- -C; 7) 5-HT 2B -/- - NdF; 8) 5-HT 2A/2B -/- -C; 9) 5-HT 2A/2B -/- -NdF; 10) 5-HT 2A -/- -C and 11) 5-HT 2A -/- - NdF and 2 groups of eNOS -/- mice 12) eNOS -/- -C and 13) eNOS -/- -NdF. Mice were monitored for hemodynamic and echocardiographic parameters. At day 28, blood 5-HT and urinary 5-HIAA concentrations were measured and hearts harvested for histological analysis. In controls, this analysis reveals mitral valve lesions with increased thickness (WT-C 35±4μm vs WT-NdF 69±9μm; p<0,05) and number of endothelial cells (+40%). Lesions are fully prevented by pharmacological and constitutive inactivation of: 5-HT 2B -R (SB 206553 or 5-HT 2B -/- mice) and both 5-HT 2A and 5-HT 2B -R (ritanserine or 5-HT 2A/2B -/- ). In 5-HT 2A -/- treated with NdF, we still observe an increased valve thickness (5-HT 2A -/- -C 45±4μm vs 5-HT 2A -/- -NdF 60±8μm) mainly due to increased cellularity. Finally, eNOS inhibition (L-NAME or eNOS -/- mice) also prevents lesions indicating the crucial role of endothelial cells in 5-HT 2B -mediated mitral valve degeneration. We demonstrate for the first time that both 5-HT 2B and 5-HT 2A -Rs are involved in drug-induced valvulopathy and the role of endothelial cells and eNOS activation.

Valvular heart surgery: evaluating the past to enlighten the future

Valvular heart surgery: evaluating the past to enlighten the future

OP-269 Computational Patient-Specific Segmentation and Modelling of Degenerative Mitral Valve Disease from 3D Echocardiography

OP-269 Computational Patient-Specific Segmentation and Modelling of Degenerative Mitral Valve Disease from 3D Echocardiography

Effects of right ventricular morphology and function on outcomes of patients with degenerative mitral valve disease

The study objective was to investigate whether, in patients undergoing surgery for degenerative mitral valve disease, associated right ventricular remodeling and dysfunction are stronger determinants of preoperative organ dysfunction and prognosis than functional tricuspid regurgitation. From January 2001 to January 2011, 4197 patients underwent primary mitral valve surgery for degenerative valve disease at Cleveland Clinic. Using a quasi-experimental enriched study design, 781 patients were randomly selected within each grade of functional tricuspid regurgitation. Renal function was assessed by glomerular filtration rate and blood urea nitrogen, and hepatic function was assessed by Model for End-stage Liver Disease (MELD) score. Preoperative and postoperative right ventricular morphology and function were measured de novo on stored echocardiographic images. To assess survival, 3471 patient-years of follow-up data were available for analysis. Several preoperative right ventricular variables, but not functional tricuspid regurgitation grade (P>.05), were associated with preoperative renal and hepatic dysfunction, but neither was associated with early mortality (<6 months after surgery). However, worse preoperative right ventricular myocardial performance index (P=.001), but not functional tricuspid regurgitation grade (P>.2), was among the risk factors for later mortality. Postoperative unadjusted right ventricular function, but not functional tricuspid regurgitation grade (P≥.2), was associated with both early (P=.04) and later (P=.01) mortality, but in multivariable analysis appeared to be a surrogate for worse preoperative condition. Together with patient comorbidities and operative factors, right ventricular morphology and function are associated more strongly with preoperative organ dysfunction and prognosis than is functional tricuspid regurgitation severity in patients undergoing surgery for degenerative mitral valve disease. Our previous study showed that tricuspid valve repair remains the most effective treatment to improve right ventricular function.

Preoperative left ventricular function in degenerative mitral valve disease

The aim of the study is to determine the impact of the underlying etiology (Barlow's disease or fibroelastic deficiency) on left ventricular function in patients with degenerative mitral valve disease and severe mitral regurgitation. We studied 233 patients (mean age: 53.8 ± 12.9) undergoing surgery for severe mitral regurgitation due to degenerative mitral valve disease at Almazov Federal Heart Centre between 2009 and 2011. Pathologic diagnoses for valvular tissue specimens were provided by an experienced pathologist. Preoperative strain and strain rate were determined using speckle tracking (Vivid 7 Dimension, EchoPAC'08). Barlow's disease was identified by the pathologist in 60 patients (25.8%), and fibroelastic deficiency in 173 patients (74.2%). There were no significant differences between groups in preoperative mitral regurgitation volume (70.5 ± 9.6 vs. 71.6 ± 8.5 ml, P = 0.40), and in global systolic (ejection fraction: 52.7 ± 6.6 vs. 52.0 ± 7.4%, P = 0.53) and diastolic (E/e': 12.2 ± 3.9 vs. 12.8 ± 4.2, P = 0.35) left ventricular function. Despite the lack of difference in ejection fraction and diastolic tissue Doppler parameters, in patients with Barlow's disease in comparison with fibroelastic deficiency a significant decrease of the left ventricular longitudinal systolic strain (-13.5 ± 2.2 vs. -15.6 ± 2.3%, P = 0.00001) and early diastolic strain rate (1.04 ± 0.20 vs. 1.14 ± 0.18 s, P = 0.0004) were detected. Patients with severe mitral regurgitation due to Barlow's disease have a lower preoperative left ventricular systolic function than those with fibroelastic deficiency, which may affect their postoperative prognosis.

Serial analysis of serum cardiac troponin I changes and correlation with clinical findings in 46 dogs with mitral valve disease

Cardiac troponin I (cTnI) is a biomarker correlated with the severity of myocardial injury. It is hypothesized that serial assessment of cTnI could provide information about the disease progression in chronic heart failure. The purpose of the study was to correlate serial serum cTnI concentrations with clinical scoring and select diagnostic imaging findings in dogs managed for mitral valve degeneration (MVD) for a period of 6 months. Client-owned dogs with MVD were prospectively recruited for the study. The dogs were allocated into 3 groups (I, II, III) according to the severity of their clinical signs based on the classification suggested by the International Small Animal Cardiac Health Council. During the 6-month study period, serum specimens for biochemical testing were obtained biweekly, clinical progression and response to treatment were also evaluated biweekly, and radiographic reevaluation was performed every 2 months. A total of 46 dogs were evaluated. There was a marked decrease in cTnI values during the first 2 weeks after initial diagnosis, more pronounced in group III, and corresponding to the initiation of therapy and clinical stabilization of animals. Serum cTnI was significantly different (P < .05) among the 3 dog groups throughout the study period. The interaction between Group and Period was significant in group III, indicating an upward cTnI trend evident in severely affected animals. A positive correlation was demonstrated in all groups between serum cTnI and clinical scoring. Long-term management of MVD in dogs could benefit from the serial measurement of cTnI.

Bronchial stent placement in a dog with bronchomalacia and left atrial enlargement

A 13-year-old neutered male Maltese was referred for paroxysms of coughing and cyanosis, with radiographic evidence of bronchial disease and cardiomegaly. Investigation with echocardiography, bronchoscopy, fluoroscopy and bronchoalveolar lavage led to a diagnosis of myxomatous mitral valve degeneration with insufficiency, ISACHC class II heart failure and bronchomalacia with severe left mainstem bronchial collapse. Persistence of intractable cough despite medical therapy prompted placement of a stent in the left mainstem bronchus. Immediately after stent placement, severe pulmonary oedema developed, thought to be due to compression of the left atrium by the stent or acute lung injury related to stent placement. The dog recovered over a 3-day period with diuretic therapy and positive end expiratory pressure ventilation. Subsequently, the dog died from congestive heart failure 102 days after stent placement, during which time occasional, self limiting coughing episodes occurred.

Longitudinal Electrocardiographic Evaluation of Dogs with Degenerative Mitral Valve Disease

BackgroundIncreased heart rate (HR) and decreased heart rate variability (HRV) are evident in some dogs with degenerative mitral valve disease (DMVD).ObjectivesEvaluation of the factors influencing HR and HRV (assessed by the vasovagal tonus index; VVTI) and their change over time in dogs with DMVD.AnimalsClient‐owned dogs (n = 257) with DMVD recruited from first opinion practice.MethodsProspective longitudinal follow‐up at six‐monthly intervals of dogs with DMVD. Dogs followed up for at least 18 months (n = 102) were grouped according to their outcome as dogs dying/euthanized because of cardiac disease (n = 28; Group 1), noncardiac disease (n = 40; Group 2) and dogs alive (n = 34; Group 3). HR and VVTI were measured on 1‐minute ECG recordings. Repeated measures linear models were constructed to investigate the factors that influence HR and VVTI and their changes over time.ResultsHeart rate and VVTI were affected by disease severity and were different in Cavaliers compared to other breeds. Group 1 and Group 2 dogs underwent an increase in HR and decrease in VVTI, evident at least 18 months before death. Group 1 had a further decrease in VVTI followed by an increase in HR approximately 1 year and 6 months before death, respectively.Conclusions and Clinical ImportanceDogs with DMVD have an increase in HR and decrease in HRV over a year before death, with greater changes in those dogs dying/euthanized because of cardiac disease. Both HR and VVTI can potentially be regarded as biomarkers for all‐cause mortality.

Pimobendan: its place in managing feline heart failure

Pimobendan, a positive inodilator, has proven to bring an added benefit when used in combination with other routine medications in the treatment of canine heart failure. In 2009, the American College of Veterinary Internal Medicine Consensus Statement recommended the use of pimobendan for treatment of dogs with congestive heart failure secondary to degenerative mitral valve disease, while in 2012 the PROTECT (Pimobendan Randomised Occult DCM Trial to Evaluate Clinical symptoms and Time to heart failure) study advocated the use of pimobendan in asymptomatic Doberman Pinscher dogs with dilated cardiomyopathy. With pimobendan being the only canine approved positive inotrope in the UK, and with its success in increasing survival times in our canine patients with heart failure, use of pimobendan in cases of feline heart failure is now being investigated as a viable option when positive inotropic effects are required.

Invited Commentary

In the 1960s, Kay and colleagues [1Kay J.H. Egerton W.S. Zubiate P. The surgical treatment of mitral insufficiency and combined mitral stenosis and insufficiency with use of the heart-lung machine.Surgery. 1961; 50: 67-74PubMed Google Scholar] and Reed and colleagues [2Reed G.E. Tice D.A. Clauss R.H. Asymmetric exaggerated mitral annuloplasty: repair of mitral insufficiency with hemodynamic predictability.J Thorac Cardiovasc Surg. 1965; 49: 752-761PubMed Google Scholar] described methods to reduce the posterior annulus by plicating the annulus at the commissures. Anchoring sutures were placed on the anterior side of the annulus at the commissure, with considerably larger bites on the posterior annulus, which decreased the length of the posterior annulus. By contrast, annuloplasty is used to support or reduce in size the posterior portion of the mitral annulus and to provide a stable foundation for appropriate alignment of the leaflets. Some surgeons use the Kay suture plication technique only if abnormalities are localized solely at the commissures, which are not the majority of cases. Also, Kay and colleagues demonstrated good results with mitral repair for patients with ischemic mitral insufficiency, but no analyses were performed to examine the impact of confounding variables. Some studies demonstrated that complications after mitral valve repair, including annuloplasty, were affected by patients' preexisting comorbidities [3Grossi E.A. Goldberg J.D. LaPietra A. et al.Ischemic mitral valve reconstruction and replacement: comparison of long-term survival and complications.J Thorac Cardiovasc Surg. 2001; 122: 1107-1124Abstract Full Text Full Text PDF PubMed Scopus (279) Google Scholar]. Sawazaki and colleagues [4Sawazaki M. Tomari S. Izawa N. Zaikokuji K. Tateishi N. Imaeda Y. Interrupted commissural band annuloplasty for degenerative mitral valve disease.Ann Thorac Surg. 2014; 97: 558-562Abstract Full Text Full Text PDF PubMed Scopus (5) Google Scholar] modified the original Kay technique in order to avoid posterior annuloplasty to prevent hemolysis and prevent mitral stenosis secondary to pannus formation. The article by Sawazaki and colleagues [4Sawazaki M. Tomari S. Izawa N. Zaikokuji K. Tateishi N. Imaeda Y. Interrupted commissural band annuloplasty for degenerative mitral valve disease.Ann Thorac Surg. 2014; 97: 558-562Abstract Full Text Full Text PDF PubMed Scopus (5) Google Scholar] reports a series of 63 patients with bilateral commissural band annuloplasty compared with 58 patients with a Cosgrove band, looking at the incidence of mitral stenosis and hemolysis that seems to favor the former technique. The incidence of these complications is generally low, and the attempt at improving the technique of Kay and colleagues does not seem to address prime considerations in the occidental setting of mitral valve repair. Definitive conclusions regarding the use of this technique can be derived only after a larger comparative study and by including numerous precisions on types of lesions, patients' preoperative characteristics, and associated procedures. Finally, on the basis of long-term studies, mitral valve repair at 10 years is durable, meaning that is carries better survival than do mechanical valves [4Sawazaki M. Tomari S. Izawa N. Zaikokuji K. Tateishi N. Imaeda Y. Interrupted commissural band annuloplasty for degenerative mitral valve disease.Ann Thorac Surg. 2014; 97: 558-562Abstract Full Text Full Text PDF PubMed Scopus (5) Google Scholar, 5DiBardino D.J. ElBardissi A.W. McClure R.S. Razo-Vasquez O.A. Kelly N.E. Cohn L.H. Four decades of experience with mitral valve repair: analysis of differential indications, technical evolution, and long-term outcome.J Thorac Cardiovasc Surg. 2010; 139 (discussion 83–74): 76-83Abstract Full Text Full Text PDF PubMed Scopus (102) Google Scholar]. Also, repair offers a better preservation of heart function, lower risk of thromboembolic events, and infection, and it does not require the use of anticoagulation. In the near future, the technique presented in this article could be added to the available methods of performing mitral repair. Interrupted Commissural Band Annuloplasty for Degenerative Mitral Valve DiseaseThe Annals of Thoracic SurgeryVol. 97Issue 2PreviewMitral annuloplasty is useful for treating degenerative mitral valve disease. Although the incidence of complications is low, prosthetic ring-related complications can occur. Hemolysis and mitral stenosis are serious complications requiring reoperation. Limited use of prosthetic material could decrease the risk for complications. Commissural annuloplasty has been reported by Kay and Reed; their techniques involve suture plication. To prevent dehiscence, we selected short bands and compared the echocardiographic changes between this method and the Cosgrove ring. Full-Text PDF

Procedural Guidance Using Advance Imaging Techniques for Percutaneous Edge-to-Edge Mitral Valve Repair

The complexity of structural heart disease interventions such as edge-to edge mitral valve repair requires integration of multiple highly technical imaging modalities. Real time imaging with 3-dimensional (3D) echocardiography is a relatively new technique that first, allows clear volumetric imaging of target structures such as the mitral valve for both pre-procedural diagnosis and planning in patients with degenerative or functional mitral valve regurgitation. Secondly it provides intra-procedural, real-time panoramic volumetric 3D view of structural heart disease targets that facilitates eye-hand coordination while manipulating devices within the heart. X-ray fluoroscopy and RT 3D TEE images are used in combination to display specific targets and movement of catheter based technologies in 3D space. This integration requires at least two different image display monitors and mentally fusing the individual datasets by the operator. Combined display technology such as this, allow rotation and orientation of both dataset perspectives necessary to define targets and guidance of structural disease device procedures. The inherently easy concept of direct visual feedback and eye-hand coordination allows safe and efficient completion of MitraClip procedures. This technology is now merged into a single structural heart disease guidance mode called EchoNavigator(TM) (Philips Medical Imaging Andover, MA). These advanced imaging techniques have revolutionized the field of structural heart disease interventions and this experience is exemplified by a cooperative imaging approach used for guidance of edge-to-edge mitral valve repair procedures.