Lewis Gregory D, Shah Ravi V, Pappagianopolas Paul P, Systrom David M, Semigran Marc J
Cardiology Division, Department of Medicine, and Pulmonary and Critical Care Unit, Massachusetts General Hospital, Harvard Medical School, 55 Fruit Street, Boston, MA 02114, USA.
Circ Heart Fail. 2008 Nov;1(4):227-33. doi: 10.1161/CIRCHEARTFAILURE.108.785501.
Ventilatory efficiency, right ventricular (RV) function, and secondary pulmonary hypertension are each prognostic indicators in patients with heart failure due to left ventricular systolic dysfunction, but the relationships among these variables have not been comprehensively investigated. In this study, we hypothesized that inefficient ventilation during exercise, as defined by an abnormally steep relationship between ventilation and carbon dioxide output (Ve/Vco(2) slope), may be a marker of secondary pulmonary hypertension and RV dysfunction in heart failure.
A cohort of patients with systolic heart failure (mean+/-SD age, 58+/-13 years; left ventricular ejection fraction, 0.27+/-0.05; peak oxygen uptake, 11.2+/-3.2 mL kg(-1) min(-1)) underwent incremental cardiopulmonary exercise testing with simultaneous hemodynamic monitoring and first-pass radionuclide ventriculography before and after 12 weeks of treatment with sildenafil, a selective pulmonary vasodilator, or placebo. Ve/Vco(2) slope was positively related to rest and exercise pulmonary vascular resistance (R=0.39 and R=0.60, respectively) and rest pulmonary capillary wedge pressure (R=0.49, P<0.005 for all) and weakly indirectly related to peak exercise RV ejection fraction (R=-0.29, P=0.03). Over the 12-week study period, Ve/Vco(2) slope fell 8+/-3% (P=0.02) with sildenafil and was unchanged with placebo. Changes in Ve/Vco(2) slope correlated with changes in exercise pulmonary vascular resistance (R=0.69, P<0.001) and rest and exercise RV ejection fraction (R=-0.58 and -0.40, respectively, both P<0.05).
In patients with systolic heart failure and secondary pulmonary hypertension, ventilatory efficiency is closely related to RV function and pulmonary vascular tone during exercise.
通气效率、右心室（RV）功能和继发性肺动脉高压均为左心室收缩功能障碍所致心力衰竭患者的预后指标，但这些变量之间的关系尚未得到全面研究。在本研究中，我们假设运动期间通气效率低下，即通气与二氧化碳排出量之间关系异常陡峭（Ve/Vco₂斜率），可能是心力衰竭患者继发性肺动脉高压和RV功能障碍的一个标志。
一组收缩性心力衰竭患者（平均±标准差年龄，58±13岁；左心室射血分数，0.27±0.05；峰值摄氧量，11.2±3.2 mL·kg⁻¹·min⁻¹）在接受选择性肺血管扩张剂西地那非或安慰剂治疗12周前后，进行递增式心肺运动试验，同时进行血流动力学监测和首次通过放射性核素心室造影。Ve/Vco₂斜率与静息和运动时的肺血管阻力呈正相关（分别为R = 0.39和R = 0.60），与静息肺毛细血管楔压呈正相关（R = 0.49，P均<0.005），与运动高峰时RV射血分数呈弱间接相关（R = -0.29，P = 0.03）。在为期12周的研究期间，西地那非治疗使Ve/Vco₂斜率下降8±3%（P = 0.02），安慰剂治疗则无变化。Ve/Vco₂斜率的变化与运动肺血管阻力的变化相关（R = 0.69，P<0.001），与静息和运动时RV射血分数的变化相关（分别为R = -0.58和-0.40，P均<0.05）。
在收缩性心力衰竭和继发性肺动脉高压患者中，运动期间通气效率与RV功能及肺血管张力密切相关。
