K.M. John Chan

Coronary artery bypass surgery with or without mitral valve annuloplasty in moderate functional ischemic mitral regurgitation: final results of the Randomized Ischemic Mitral Evaluation (RIME) trial.

Background—The role of mitral valve repair (MVR) during coronary artery bypass grafting (CABG) in patients with moderate ischemic mitral regurgitation (MR) is uncertain. We conducted a randomized, controlled trial to determine whether repairing the mitral valve during CABG may improve functional capacity and left ventricular reverse remodeling compared with CABG alone. Methods and Results—Seventy-three patients referred for CABG with moderate ischemic MR and an ejection fraction >30% were randomized to receive CABG plus MVR (34 patients) or CABG only (39 patients). The study was stopped early after review of interim data. At 1 year, there was a greater improvement in the primary end point of peak oxygen consumption in the CABG plus MVR group compared with the CABG group (3.3 mL/kg/min versus 0.8 mL/kg/min; P<0.001). There was also a greater improvement in the secondary end points in the CABG plus MVR group compared with the CABG group: left ventricular end-systolic volume index, MR volume, and plasma B-type natriuretic peptide reduction of 22.2 mL/m2, 28.2 mL/beat, and 557.4 pg/mL, respectively versus 4.4 mL/m2 (P=0.002), 9.2 mL/beat (P=0.001), and 394.7 pg/mL (P=0.003), respectively. Operation duration, blood transfusion, intubation duration, and hospital stay duration were greater in the CABG plus MVR group. Deaths at 30 days and 1 year were similar in both groups: 3% and 9%, respectively in the CABG plus MVR group, versus 3% (P=1.00) and 5% (P=0.66), respectively in the CABG group. Conclusions—Adding mitral annuloplasty to CABG in patients with moderate ischemic MR may improve functional capacity, left ventricular reverse remodeling, MR severity, and B-type natriuretic peptide levels, compared with CABG alone. The impact of these benefits on longer term clinical outcomes remains to be defined. Clinical Trial Registration—URL: http://www.clinicaltrials.gov. Unique identifier: NCT00413998.

Towards comprehensive assessment of mitral regurgitation using cardiovascular magnetic resonance.

Cardiovascular magnetic resonance (CMR) is increasingly used to assess patients with mitral regurgitation. Its advantages include quantitative determination of ventricular volumes and function and the mitral regurgitant fraction, and in ischemic mitral regurgitation, regional myocardial function and viability. In addition to these, identification of leaflet prolapse or restriction is necessary when valve repair is contemplated. We describe a systematic approach to the evaluation of mitral regurgitation using CMR which we have used in 149 patients with varying etiologies and severity of regurgitation over a 15 month period.Following standard ventricular cine acquisitions, including 2, 3 and 4 chamber long axis views and a short axis stack for biventricular function, we image movements of all parts of the mitral leaflets using a contiguous stack of oblique long axis cines aligned orthogonal to the central part of the line of coaptation. The 8–10 slices in the stack, orientated approximately parallel to a 3-chamber view, are acquired sequentially from the superior (antero-lateral) mitral commissure to the inferior (postero-medial) commissure, visualising each apposing pair of anterior and posterior leaflet scallops in turn (A1-P1, A2-P2 and A3-P3). We use balanced steady state free precession imaging at 1.5 Tesla, slice thickness 5 mm, with no inter-slice gaps. Where the para-commissural coaptation lines curve relative to the central region, two further oblique cines are acquired orthogonal to the line of coaptation adjacent to each commissure. To quantify mitral regurgitation, we use phase contrast velocity mapping to measure aortic outflow, subtracting this from the left ventricular stroke volume to calculate the mitral regurgitant volume which, when divided by the left ventricular stroke volume, gives the mitral regurgitant fraction. In patients with ischemic mitral regurgitation, we further assess regional left ventricular function and, with late gadolinium enhancement, myocardial viability.Comprehensive assessment of mitral regurgitation using CMR is feasible and enables determination of mitral regurgitation severity, associated leaflet prolapse or restriction, ventricular function and viability in a single examination and is now routinely performed at our centre. The mitral valve stack of images is particularly useful and easy to acquire.

Mitral valve surgery.

In Western developed countries, mitral valve surgery usually involves degenerative or Barlow’s valve diseases causing mitral regurgitation; the mitral valve can usually be repaired successfully. However, in developing countries, rheumatic mitral valve diseases causing mitral stenosis or regurgitation or both, is still common and repairing these valves can be more challenging.

Functional tricuspid regurgitation: A more complex entity than it appears

The optimal management of patients with functional tricuspid regurgitation (TR) at the time of left-sided heart-valve surgery continues to cause controversy. It is well recognised that patients with severe functional TR should have concomitant tricuspid-valve repair, but the management of mild or moderate TR at the time of left-sided heart-valve surgery continues to be debated.1 In this issue of the journal, Song et al (see article on page 931) address the very important question of whether mild TR should be surgically addressed during left-sided heart-valve surgery.2 In a retrospective study of 638 patients who underwent left-sided heart-valve surgery without tricuspid valve surgery, 548 patients had none or trace TR (grade 0–1/4), and 90 patients had mild TR (grade 2/4). At a mean follow-up of 64 months, moderate or severe TR developed in 7.3% in those who had none or trace TR, and in 20% in those who had mild TR. Compared with patients who did not develop significant late TR, patients who developed significant late TR had a higher late mortality (16.3% vs 4.9%, p = 0.004) and a lower event-free survival (76% vs 91%, p<0.001). Limitations to this study include: 1. It is a retrospective study and measurements of TR grade and tricuspid annulus size were done retrospectively. It is well recognised that retrospective assessment of such parameters is not as accurate as real-time assessment, as adequate imaging views may not have been obtained. Moreover, a single preoperative echo measurement of TR severity done at rest may not reflect the true severity of TR, as this is dependent on right ventricular (RV) preload, afterload and contractility. 2. The aetiology of the left-sided heart-valve lesion included a high proportion of patients with rheumatic valve disease (45%). Although the authors report that there was no rheumatic involvement of the tricuspid valve by …

Rheumatic Mitral Valve Disease: Current Surgical Status

Rheumatic heart disease is the most serious sequelae of rheumatic fever occurring in approximately 30% of rheumatic fever patients. Patients with acute rheumatic fever may develop varying degrees of pancarditis with associated valve disease, heart failure, and pericarditis. Worldwide, rheumatic heart disease remains a major health problem although its prevalence in the developed countries is much reduced. Involvement of the mitral valve results in mitral regurgitation and/or stenosis. Where surgery is indicated, mitral valve replacement is usually necessary although in some cases, mitral valve repair is possible.

External aortic root support for Marfan syndrome: early clinical results in the first 20 recipients with a bespoke implant.

Summary Objectives Fatal aortic dissection occurs at young age in Marfan syndrome. Prevention relies on elective replacement of the aortic root. The placement of an external aortic root support, tailored to the anatomy of the individual patient has been proposed as a feasible alternative. Design, setting and main outcome measures External aortic root support was offered to patients with Marfan syndrome with aortic root diameter of 40–55 mm and without aortic regurgitation. By computer-aided design, a model of the individual patients aorta was created from cardiac magnetic resonance images and a bespoke external aortic support was manufactured. Comparative measurements were made of the ascending aorta at the level of closure of the aortic valve cusps from magnetic resonance imaging studies taken preoperatively, at first follow-up, and at most recent follow-up. For patients having aortic root surgery at the same institution, in the same time frame as the first 10 patients, clinical data were retrieved on Marfan and other patients having aortic root replacement to serve as a reference data. Results Twenty patients were operated upon from May 2004 to October 2009, 13 men and 7 women, median age 33 years. All 20 patients are alive and well at the time of last follow-up. Preoperative aortic diameters were 40–54 mm. All postoperative images were satisfactory with an overall reduction in aortic root dimensions. The surgery took half the time of other aortic root surgery. Cardiopulmonary bypass was used only in the first patient, myocardial ischemia was not required in any patient, and no postoperative anticoagulation is mandated. Conclusions The primary objective of this surgery was fully achieved in 19 of the 20 patients, reinforcing the ascending aorta while leaving the native aortic valve intact and conserving the blood/endothelium interface.

Truly stentless autologous pericardial aortic valve replacement: an alternative to standard aortic valve replacement.

OBJECTIVE The aim of this study was to determine the feasibility and durability of truly stentless aortic valve replacement using autologous pericardium sutured directly onto the aortic wall. METHODS Eleven patients (mean age, 55.9 years) requiring aortic valve replacement were recruited. A circular piece of pericardium about 8 cm in diameter was harvested and treated in 0.6% glutaraldehyde for 10 minutes. The aortic valve was excised and, with the use of specially designed instruments (CardioMend LLC, Santa Barbara, Calif), the sinotubular junction was sized and the pericardium was tailored to the required size and shape and then sutured directly onto the aortic wall. The reconstructed valve was assessed directly and by echocardiography at the end of the operation; it was assessed by echocardiography and cardiac magnetic resonance imaging at 6 months and yearly. Computed tomographic scan of the aortic valve to assess for valve calcification was performed at last follow-up. RESULTS Hospital mortality was 0%. Mean follow-up was 6.5 years (range, 5.3-7.5 years). Freedom from structural valve deterioration, thromboembolism, endocarditis and reoperation was 100%, 100%, 72.7%, and 63.6%, respectively. There were 4 reoperations at 4, 13, 15, and 46 months, 3 of them owing to endocarditis and 1 owing to technical failure noted at the time of surgery. The remaining 7 patients are alive and well with a mean New York Heart Association class of 1.3 and normally functioning aortic valves with no calcification. CONCLUSIONS Truly stentless aortic valve replacement using autologous pericardium sutured directly onto the aortic wall is safe and feasible and has excellent durability up to 7.5 years with no calcification.

Ischemic mitral regurgitation:in search of the best treatment for a common condition

Ischemic mitral regurgitation (IMR) is common after myocardial infarction. It results in a significantly increased risk of congestive heart failure and death. The assessment of these patients is challenging as IMR is a dynamic condition and varies in severity under different physiologic conditions, such as physical exertion and changes in left ventricle (LV) contractility. Assessment, therefore, includes both the mitral valve and the LV and needs to be done at rest and under conditions of stress. Treatment of IMR involves optimization of medical therapy for coronary artery disease, coronary artery revascularization, and mitral valve surgery. Most patients have mild IMR and undergo isolated coronary artery revascularization either by percutaneous coronary intervention or coronary artery bypass graft surgery (CABG). In those with severe IMR, mitral valve repair or replacement is indicated, especially if the patient is symptomatic or has impaired LV function or LV dilatation. The optimal treatment of moderate IMR is controversial; mitral valve repair at the time of CABG may be beneficial, but randomized controlled trials are needed. In selected patients with papillary muscle dyssynchrony, cardiac resynchronization therapy may also be helpful.

Tricuspid Valve Disease: Pathophysiology and Optimal Management

Tricuspid valve disease most commonly occurs secondary to left-sided heart valve disease, in particular mitral valve disease. It is a marker of adverse outcome, and patients with moderate or severe tricuspid regurgitation (TR) have a reduced survival rate. Primary TR is treated surgically if severe, and the patient is symptomatic. However, during concomitant left-sided heart valve surgery, moderate or severe secondary TR with either raised pulmonary artery pressures or tricuspid annular dilatation should also be treated. This article reviews the pathophysiology and current management of patients with tricuspid valve disease.

Hypertrophic obstructive cardiomyopathy: the mitral valve could be the key

OBJECTIVES As we strongly believe that treating the mitral valve abnormalities is a key feature of hypertrophic obstructive cardiomyopathy (HOCM), we have systematically corrected both the anterior and posterior leaflet (PL) size and geometry. We have analysed our immediate results and at mid-term follow-up. METHODS From March 2010 until June 2015, 16 patients with HOCM underwent surgical correction of obstruction. The mean age was 51 years old (range, 32-72 years). All were symptomatic being New York Heart Association (NYHA) class 3 (n = 4) or 4 (n = 12). All had systolic anterior motion at echocardiogram with severe mitral regurgitation (MR). Intraventricular gradient preoperatively was 73.5 mmHg (range, 50-120 mmHg). All patients underwent a double-stage procedure: first septal resection through (i) the aortic valve and (ii) the detached anterior leaflet (AL) of the mitral valve and at second, mitral valve repair by (i) reducing PL height (leaflet resection or artificial neochordae) (ii) increasing AL height with pericardial patch. RESULTS There was no in-hospital or late death. All patients were Class 1 NYHA at latest follow-up. Control echocardiography showed no MR, mean rest intraventricular gradient was 15 mmHg (range, 9-18 mmHg). CONCLUSIONS Our good mid-term results support the concept that HOCM is not only a septal disease and that the mitral valve pathology is a key component that should be addressed. For most patients, the ideal surgical treatment should consist in a two-step procedure. It is even necessary to be studied whether treating the mitral valve alone could not suffice.