Age and body surface area dependency of mitral valve and papillary apparatus parameters: assessment by real-time three-dimensional echocardiography.

AIMS: Real-time three-dimensional echocardiography (RT3DE) has been used to quantify mitral valve (MV) annular size and leaflet tenting parameters in small numbers of patients with different pathologies. We sought to establish normal values for RT3DE mitral annular, tenting, and papillary muscle parameters over a wide age range and to study their age and body surface area (BSA) dependency. METHODS AND RESULTS: Transthoracic wide-angled RT3DE images of the MV were acquired in 120 subjects (52 females, 68 males, age: 37+/-20 years) with normal left ventricular (LV) function, no risk factors, and less than or equal to mild mitral regurgitation. Custom software (RealView) was used to trace the MV annulus, leaflets, and the papillary apparatus in mid-systole in 18 sequential cut planes obtained from the 3D data sets. Mitral valve annular area and height as well as tenting parameters (maximum and mean tenting height and mid-systolic tenting volume) were obtained and correlated with age and BSA. Wide inter-subject variability was noted in all parameters. Despite this variability, parameters directly affected by LV size were found to be BSA-dependent: MV annular area showed highest correlation with BSA (r=0.78), followed by inter-papillary distance (r=0.58) and postero-medial (PM) and antero-lateral (AL) papillary muscle annular distance (r=0.57 and r=0.46, respectively). Age did not correlate with either annular or tenting parameters, but showed moderate negative correlation with inter-papillary muscle angle (r= -0.52) and mild negative correlation with inter-papillary distance (r= -0.32), both normalized by BSA. CONCLUSIONS: Real-time three-dimensional echocardiography-derived MV annular, tenting, and papillary muscle parameters vary widely in normal subjects. When used clinically, normal values of parameters that are age- and/or BSA-dependent need to be adjusted accordingly.

Reduced coronary flow reserve in patients with congestive heart failure assessed by transthoracic Doppler echocardiography.

BACKGROUND: Although coronary flow reserve (CFR) has been reported to be restricted in various conditions, there has been no report of CFR for patients with congestive heart failure (CHF). The purpose of this study was to assess coronary flow characteristics for patients with CHF. METHODS: We studied 15 patients with CHF: 8 with dilated myocardiopathy and 7 with hypertensive heart disease. Phasic coronary flow velocities were obtained in the left anterior descending coronary artery at rest and during hyperemia (0.15 mg/kg/min adenosine triphosphate infusion intravenously) by transthoracic echocardiography before and after treatment of CHF. CFR was obtained from the ratio of hyperemic/baseline diastolic mean velocity. RESULTS: CFR was significantly restricted in the condition of CHF compared with that after improvement of CHF (1.5 +/- 0.2 vs 2.0 +/- 0.3, P < .01). Baseline diastolic mean velocity in the condition with CHF was significantly greater than that after improvement of CHF (41 +/- 13 cm/s vs 33 +/- 13 cm/s, P = .04), although maximal hyperemic diastolic mean velocity was not significantly different before and after improvement of CHF (63 +/- 20 cm/s vs 61 +/- 19 cm/s, P = .68). After improvement of CHF, heart rate, along with left ventricular end-diastolic volume and dimension, were significantly decreased, and deceleration time of transmitral early filling flow was increased compared with before treatment of CHF. Blood pressure and ejection fraction were not significantly different before and after treatment of CHF. CONCLUSIONS: Restriction of CFR is demonstrated during CHF because of the elevation of baseline resting flow velocity, which might be related to increase in left ventricular preload and heart rate.

Quantitative measurement of mitral valve coaptation in functional mitral regurgitation: In vivo experimental study by real-time three-dimensional echocardiography.

BACKGROUND: The degree of mitral valve (MV) coaptation should be an important parameter in the assessment of functional mitral regurgitation (MR). This study aimed to quantify the degree of MV coaptation in experimental models of functional MR caused by acute left ventricular (LV) pressure overload, using real-time three-dimensional (3D) echocardiography. METHODS AND RESULTS: Using canine models, LV pressure overload was induced by staged ascending aortic banding. Echocardiographic examinations were performed before and during the aortic banding. By using a novel software system for 3D quantification (REALVIEW®), the annulus and leaflet were traced manually both at the onset of MV closure and at the maximum MV closure. The coaptation index was calculated by the following formula: [(3D tenting surface area at the onset of MV closure-3D tenting surface area at the maximum MV closure)/3D tenting surface area at the onset of MV closure] x 100. MR area gradually increased with the decrease in coaptation index during progressively exacerbated aortic banding. MR area was significantly correlated with the coaptation index. A coaptation index < 12 had a high sensitivity and specificity in the presence of significant MR. CONCLUSIONS: The degree of MV coaptation can be quantified using 3D echocardiography. The coaptation index should be a useful parameter in the assessment of functional MR.

Chordal translocation for ischemic mitral regurgitation may ameliorate tethering of the posterior and anterior mitral leaflets.

OBJECTIVE: Treatment of ischemic mitral regurgitation accompanied by strong tethering remains a challenge. Undersized ring annuloplasty is frequently associated with residual/recurrent mitral regurgitation caused by mitral-leaflet tethering. Although chordal cutting is a simple procedure for repairing severe tethering of the anterior mitral leaflet, it often affects mitral valvular-ventricular continuity. In this study, using 3-dimensional echocardiography, we investigated the effects of "chordal translocation" on the geometry of the mitral components in a canine model of acute ischemic mitral regurgitation. METHODS: In 6 mongrel dogs, under cardiopulmonary bypass with cardiac arrest, artificial chordae were implanted to each papillary-muscle tip and passed through the midseptal annulus to an external tourniquet to control the tension of the stitch thereafter. Subsequently, secondary chordae were cut near their point of attachment to the anterior leaflet. After weaning from cardiopulmonary bypass, acute ischemic mitral regurgitation was induced by ligating the obtuse marginal branches. We obtained data in 2 states of the artificial chordae: relaxation (simulating chordal cutting) and gentle traction (simulating chordal translocation). RESULTS: In the chordal translocation state versus the chordal cutting state, the left ventricle ejection fraction (42.6% +/- 2.9% vs 33.2% +/- 2.3%, P < .0001), preload recruitable stroke work (54.8 +/- 2.7 mm Hg vs 34.1 +/- 2.2 mm Hg, P = .0002), and end-systolic elastance (6.7 +/- 0.5 mm Hg/mL vs 4.2 +/- 0.2 mm Hg/mL, P = .0013) improved markedly. The mitral-valve tethering volume, defined as the volume enclosed by the mitral annulus and 2 leaflets, was smaller in the chordal translocation state than in the chordal cutting state (812 +/- 88 mm(3) vs 1213 +/- 41 mm(3), P = .03). In the chordal translocation state (CT-1 and CT-2) versus the chordal cutting state, the posterior mitral-leaflet tethering area (15.7 +/- 0.7 mm(2) vs 25.1 +/- 1.2 mm(2), P < .0001 for CT-1 and 15.0 +/- 0.7 mm(2) vs 25.1 +/- 1.2 mm(2), P < .0001 for CT-2) showed a greater improvement than the anterior mitral-leaflet tethering area (41.0 +/- 0.7 mm(2) vs 46.1 +/- 1.3 mm(2) for CT-1, P = .01 and 812 +/- 88 mm(2) vs 1213 +/- 41 mm(2) for CT-2, P = .03). The mitral annular geometry did not differ between the states. CONCLUSION: Compared with chordal cutting alone, chordal translocation improved both the left ventricle function and mitral geometry in a canine model of acute ischemic mitral regurgitation. Chordal translocation may be beneficial because it ameliorates the tethering of both the anterior and posterior leaflets, which is aggravated by mitral annuloplasty alone.

Three-dimensional quantitation of mitral valve coaptation by a novel software system with transthoracic real-time three-dimensional echocardiography.

We investigated the degree of mitral valve coaptation with a custom quantitation software system using transthoracic three-dimensional (3D) echocardiography. With real-time 3D echocardiography, we obtained transthoracic volumetric images in 20 healthy subjects and 20 patients with dilated cardiomyopathy. With our novel software system, the surface area of mitral valve tenting in the onset of mitral leaflet closure [O] and the timing of maximum closure of mitral leaflet [M] were reconstructed for quantitative measurement. The coaptation index was calculated by the following formula: [(3D tenting surface area in O-3D tenting surface area in M)/3D tenting surface area in O]. The coaptation index in patients with dilated cardiomyopathy was significantly smaller than that in healthy subjects (11% +/- 4.1% vs. 18% +/- 8.0%, P = .004). The custom quantitation software system with 3D echocardiography allowed us to assess the degree of mitral valve coaptation.

Peri-infarct ischemia determined by cardiovascular magnetic resonance evaluation of myocardial viability and stress perfusion predicts future cardiovascular events in patients with severe ischemic cardiomyopathy.

BACKGROUND: We assessed whether cardiovascular magnetic resonance imaging (CMR) of peri-infarct ischemia provides prognostic information in severe ischemic cardiomyopathy (ICM) patients referred for revascularization. METHODS: Twenty-one patients with severe ICM were recruited prospectively for combined stress adenosine perfusion, late gadolinium enhancement, and rest perfusion studies. The patients were followed for in-hospital and post-discharge cardiovascular events. RESULTS: During 12+/- 9.8 months follow-up, 67% of the patients with peri-infarct ischemia and 13% of the patients without peri-infarct ischemia had cardiovascular events (p = 0.03). CONCLUSION. In severe ICM patients, the presence of peri-infarct ischemia was associated with a higher incidence of cardiovascular events.

Evaluation of bioavailability of nitric oxide in coronary circulation by direct measurement of plasma nitric oxide concentration.

Although bioavailability of NO in the coronary circulation is commonly evaluated by acetylcholine (ACh)-induced vasodilation, a change in plasma NO concentration and its relation to the flow response after injection of ACh are still unknown. Thus, we directly measured the concentration of NO in the coronary sinus by using a catheter-type NO sensor for coronary sinus. An NO-sensitive sensor was located and fixed in a 4-Fr catheter with a soft tip for protection of vascular wall. After calibration with an NO-saturated pure water, the catheter-type NO sensor was located in the coronary sinus in anesthetized dogs. The coronary flow velocity (CFV) was measured with a Doppler guide wire. Intracoronary injection of ACh (0.4 and 1.0 microg/kg) increased plasma NO concentration in a dose-dependent manner (3-10 nM). Although ACh increased CFV by 95%, there was no significant difference between the two ACh doses. After ACh, the peak value of plasma NO concentration was observed significantly later than CFV. N(G)-methyl-L-arginine (NO synthase inhibitor) decreased basal NO concentration by 3 nM and suppressed the ACh-induced NO synthesis with no significant change in average peak velocity. We conclude that production of NO in the coronary circulation can be evaluated in the coronary sinus. Although ACh increases both CFV and NO concentration, CFV dose not reflect NO concentration in terms of magnitude and time course. Direct measurement of plasma NO concentration by the catheter-type NO sensor is useful to evaluate bioavailability of NO in the coronary circulation.

[Bilateral coronary ostial stenosis after aortic valve replacement with freestyle stentless bioprosthesis: a case report].

An 80-year-old woman underwent aortic valve replacement with Freestyle stentless prosthetic valve for the stenosis. Four months later, she was admitted with myocardial ischemia. Coronary angiography revealed severe stenosis in the ostium of both right and left coronary arteries. Coronary artery bypass grafting was performed. One year later, percutaneous coronary intervention was carried out for the bilateral coronary arteries because of unstable angina. Intravascular ultrasonography demonstrated localized, membranous, homogeneous, and severe stenoses in the ostium of the right and left coronary arteries. Histological examination of a specimen taken by directional coronary atherectomy showed intimal hypertrophy, mucinous degeneration, and hyaline degeneration without reactive change. There were no findings of atherosclerosis. These clinical, angiographical histological and intravascular ultrasonography findings suggest that the immunological reaction to the heterograft was the mechanism of the bilateral ostial coronary arteries stenoses in the present case. The possibility of immunological reaction after aortic valve replacement with heterograft should be considered. There have been no report on intravascular echocardiographic and histological findings.

[Relationship between coronary flow reserve and recovery of regional left ventricular function in patients with tako-tsubo-like transient left ventricular dysfunction].

OBJECTIVES: This study assessed the relationship between coronary flow reserve and functional recovery of left ventricular wall motion in patients with tako-tsubo-like transient left ventricular dysfunction. METHODS: Coronary flow reserve was measured using the Doppler guide wire technique in the left descending coronary artery in nine consecutive patients (three men, six women, mean age 71 +/- 11 years) with tako-tsubo-like transient left ventricular dysfunction. Regional wall motion was analyzed to estimate anterior wall motion score index (anterior WMSI) by transthoracic echocardiography on admission and 3 weeks after the onset of symptoms. RESULTS: Anterior WMSI was 2.2 +/- 0.4 on admission and improved to 1.4 +/- 0.5 at 3 weeks later (p < 0.001). Coronary flow reserve on admission was not correlated to the anterior WMSI on admission (r = 0.19, p = 0.63). However, coronary flow reserve on admission was correlated to the improvement in anterior WMSI (r = 0.74, p = 0.02). CONCLUSIONS: Coronary microcirculation is damaged in acute phase of tako-tsubo-like transient left ventricular dysfunction. The severity of coronary microvascular dysfunction influences the degree of left ventricular wall motion recovery.