二尖瓣环成形术作为衰竭左心室的心室修复方法：一项初步研究。

Mitral annuloplasty as a ventricular restoration method for the failing left ventricle: a pilot study.

作者信息

Koyama Tadaaki, Soga Yoshiharu, Unimonh Oriyanhan, Nishimura Kazunobu, Komeda Masashi

机构信息

Department of Cardiovascular Surgery, Kyoto University, Graduate School of Medicine, Kyoto, Japan.

出版信息

J Heart Valve Dis. 2007 Mar;16(2):195-9.

PMID:17484470

Abstract

BACKGROUND AND AIM OF THE STUDY

Undersized mitral annuloplasty (MAP) is effective in patients with dilated cardiomyopathy and functional mitral regurgitation (MR) since, as well as addressing the MR, the MAP may also reshape the dilated left ventricular (LV) base. However, the direct benefits of this possible reshaping on LV function in the absence of underlying MR remain incompletely understood. The study aim was to identify these benefits in a canine model of acute heart failure.

METHODS

Six dogs underwent MAP with a prosthetic band on the posterior mitral annulus, using four mattress sutures. The sutures were passed individually through four tourniquets and exteriorized untied via the left atriotomy. Sonomicrometry crystals were implanted around the mitral annulus and left ventricle to measure geometry and regional function. Acute heart failure was induced by propranolol and volume loading after weaning from cardiopulmonary bypass; an absence of MR was confirmed by echocardiography. MAP was accomplished by cinching the tourniquets. Data were acquired at baseline, after induction of acute heart failure, and after MAP.

RESULTS

MAP decreased mitral annular dimensions in both commissure-commissure and septal-lateral directions. Concomitantly, the diastolic diameter of the LV base and LV sphericity decreased (i.e., improved) from 37.4 +/- 9.3 to 35.9 +/- 10 mm (p = 0.063), and from 67.9 +/- 18.6% to 65.3 +/- 18.9% (p = 0.016), respectively. Decreases were evident in both LV end-diastolic pressure (from 17 +/- 7 to 15 +/- 6 mmHg, p = 0.0480 and Tau (from 48 +/- 8 to 45 +/- 8 ms, p <0.01), while fractional shortening at the LV base increased from 7.7 +/- 4.5% to 9.4 +/- 4.5% (p = 0.045). After MAP, increases were identified in both cardiac output (from 1.54 +/- 0.57 to 1.65 +/- 0.57 1/min) and Emax (from 1.86 +/- 0.9 to 2.41 +/- 1.31 mmHg/ml).

CONCLUSION

The data acquired suggest that isolated MAP may have certain benefits on LV dimension/function in acute heart failure, even in the absence of MR. However, further investigations are warranted in a model of chronic heart failure.

摘要

研究背景与目的

小号二尖瓣环成形术（MAP）对扩张型心肌病合并功能性二尖瓣反流（MR）患者有效，因为除了解决二尖瓣反流外，MAP还可能重塑扩张的左心室（LV）基部。然而，在不存在潜在二尖瓣反流的情况下，这种可能的重塑对左心室功能的直接益处仍未完全明确。本研究的目的是在急性心力衰竭犬模型中确定这些益处。

方法

6只犬通过在二尖瓣后环放置带垫片的缝线进行MAP，使用4根褥式缝线。缝线分别穿过4个止血带，通过左心房切口引出但不打结。在二尖瓣环和左心室周围植入超声微测晶体以测量几何形状和局部功能。在体外循环撤机后通过普萘洛尔和容量负荷诱导急性心力衰竭；通过超声心动图确认无二尖瓣反流。通过收紧止血带来完成MAP。在基线、急性心力衰竭诱导后和MAP后采集数据。

结果

MAP使二尖瓣环在瓣环-瓣环和间隔-侧壁方向的尺寸均减小。同时，左心室基部的舒张直径和左心室球形度分别从37.4±9.3降至35.9±10mm（p = 0.063），以及从67.9±18.6%降至65.3±18.9%（p = 0.016）。左心室舒张末期压力（从17±7降至15±6mmHg，p = 0.0480）和等容舒张时间常数（从48±8降至45±8ms，p<0.01）均明显降低，而左心室基部的缩短分数从7.7±4.5%增加至9.4±4.5%（p = 0.045）。MAP后，心输出量（从1.54±0.57增加至1.65±0.57l/min）和Emax（从1.86±0.9增加至2.41±1.31mmHg/ml）均增加。