Chronic aortic counterpulsation with latissimus dorsi in heart failure: clinical follow-up.

BACKGROUND: Dynamic aortomyoplasty is an alternative technique to heart transplantation. The goal of our study was to evaluate the benefits of aortic counterpulsation obtained by dynamic thoracic aortomyoplasty in patients with heart failure refractory to pharmacologic treatment and contraindications to heart transplant or cardiomyoplasty. METHODS: In this study we compared preoperative and postoperative data from five out of six carefully selected patients who were treated with dynamic thoracic aortomyoplasty. This surgical technique wraps the right latissimus dorsi muscle flap around the ascending aorta. This muscle flap was electrically stimulated during diastole, following a muscle-conditioning protocol, to obtain diastolic augmentation. At the 6-month follow-up period we evaluated, invasively and noninvasively, the hemodynamic and clinical effects of aortomyoplasty. RESULTS: We observed a significant decrease in the number of hospitalizations (P = 0.01), NYHA functional class (P = 0.01), cardiothoracic ratio (P = 0.02), right ventricular diameter (P = 0.03), left atrial diameter (P = 0.04), and pulmonary artery systolic pressure (P = 0.04); and a significant increase in the 6-minute walking test (P = 0.01), cardiac index (P = 0.04), noninvasive evaluation of diastolic augmentation (P = 0.01), left ventricular shortening fraction (P = 0.01), and radioisotopic left ventricular ejection fraction (P = 0.02). We also found a nonsignificant decrease in the left ventricular diameter (P = 0.08) and wedge pressure (P = 0.19); and a nonsignificant increase in peak oxygen consumption (P = 0.13). CONCLUSIONS: Dynamic thoracic aortomyoplasty in heart failure resulted in an important improvement of hemodynamic parameters, heart functional data, and clinical functional class, when comparing preoperative data with the 6-month follow-up data.

Benefits of aortic and pulmonary counterpulsation using dynamic latissimus dorsi myoplasty.

BACKGROUND: Intraaortic and pulmonary artery counterpulsation are useful techniques to support circulation during either left or right ventricular dysfunction. Electrically stimulated skeletal muscles wrapped around the aorta, used as means of cardiac failure treatment, have proved to be an effective method of handling experimental left ventricular failure. In this article we report an induced cardiac failure model in acute open chest dogs and describe the hemodynamic improvement of simultaneous aortic and pulmonary artery counterpulsation. METHODS: This was achieved with a bilateral latissimus dorsi muscle flap, stimulated with a software written in C++ for Windows. Dynamic aortomyoplasty was performed using the left latissimus dorsi muscle flap around the descending aorta, and dynamic pulmonaromyoplasty was achieved wrapping the pulmonary trunk with the right latissimus dorsi muscle flap. In all animals blood pressures and cardiac output were measured after cardiac failure induced by a high-dose of propranolol hydrochloride (3 mg/kg intravenously) before and after latissimus dorsi muscle flap stimulation. RESULTS: Aortopulmonary counterpulsation resulted in a significant increase in mean aortic pressure, mean pulmonary pressure, and cardiac output. In addition, a significant decrease was observed in end-diastolic left ventricular pressure, systemic vascular resistance, and pulmonary vascular resistance. Subendocardial viability index (diastolic pressure-time index/systolic tension-time index) in aortomyoplasty and tension time index in pulmonaromyoplasty showed significant improvement when cardiac assistance was performed by electrical stimulation of both muscles (p = 0.037 and p = 0.001, respectively). CONCLUSIONS: Treatment of experimentally induced cardiac failure using aortopulmonary counterpulsation allows effective hemodynamic improvement in open-chest dogs.

Dynamic abdominal and thoracic aortomyoplasty in heart failure: assessment of counterpulsation.

BACKGROUND: Aortic counterpulsation, either biologic or mechanical, is a useful technique to support circulation during left ventricular dysfunction. METHODS: In this study we used an induced cardiac failure model in acute open chest sheep to compare hemodynamic improvements between thoracic and abdominal aortic counterpulsation. This was achieved with left latissimus dorsi and left hemidiaphragm muscle flaps. RESULTS: Thoracic and abdominal aortic counterpulsation in heart failure resulted in a significant improvement of hemodynamic parameters. Subendocardial viability index, defined as diastolic pressure-time index to systolic tension-time index, in thoracic and abdominal aortomyoplasty showed significant improvement (p<0.05) when cardiac assistance was performed by electrical stimulation of each muscle flap. A new counterpulsation index derived from diastolic and systolic areas beneath the aortic pressure curve was tested, obtaining a correlation coefficient with the subendocardial viability index of 0.758 (p<0.001). Values of subendocardial viability index and counterpulsation index showed minimal variability. CONCLUSIONS: Treatment of experimentally induced cardiac failure with dynamic abdominal aortic counterpulsation allows an effective hemodynamic improvement in open chest sheep. Furthermore, this diastolic arterial pressure augmentation could be evaluated through a new counterpulsation index derived from diastolic and systolic areas beneath the aortic pressure curve.

[Assisted circulation to the right ventricle through pulmonary counterpulsation using a biological method]. / Assistência circulatória ao coração direito através da contrapulsação pulmonar usando-se um método biológico.

PURPOSE: To study the hemodynamic effects of latissimus dorsi dynamic pulmonaroplasty in open chest animals. METHODS: Six anesthetized mongrel dogs were subjected to diastolic counterpulsation using electrically stimulated latissimus dorsi muscle flap wrapped around the aortic and pulmonary arteries roots and gated to the surface electrocardiogram. Aortic and Pulmonanary pressures as well as cardiac output and cardiac index were measured. RESULTS: Diastolic counterpulsation resulted in a significant increase in cardiac output (from 2.35 +/- 0.26 to 2.45 +/- 0.28 l/min) (p < 0.005) and cardiac index (from 0.108 +/- 0.020 to 0.113 +/- 0.020 l/min/kg) (p < 0.05). The diastolic pulmonary arterial efficiency index showed a significant increase when latissimus dorsi stimulation was on (from 8.37 +/- 0.60 to 11.65 +/- 0.83 mmHg); (p < 0.005). CONCLUSION: Latissimus dorsi dynamic pulmonaroplasty provides an effective means of arterial counter pulsation in open chest dogs.

Hemodynamic effects of cardiomyoplasty in an experimental model of acute heart failure and atrial fibrillation.

The aim of our work was to study the hemodynamic effects of dynamic cardiomyoplasty on an acute animal model of atrial fibrillated heart failure. Eight anesthetized open chest dogs suffering from atrial fibrillation and heart failure, obtained by topic acetylcholine and propranolol, were treated by a cardiomyoplasty procedure performed with an electrostimulated latissimus dorsi muscle flap (LDMF). Values considered for analysis during LDMF stimulation were selected from cardiac cycles with R-R intervals similar to those when the LDMF was not stimulated (+/- 20 ms). Atrial fibrillated heart failure showed a significant increase of systemic vascular resistance, end diastolic left ventricular pressure (EDLVP) and right atrial pressure (p < 0.05), and a significant decrease in cardiac output, systolic left ventricular pressure (SLVP), and mean aortic pressure (p < 0.05) compared with control values. LDMF stimulation in atrial fibrillated heart failure resulted in a significant increase of SLVP, cardiac output, and mean aortic pressure (p < 0.05) and a significant decrease of systemic vascular resistance, EDLVP, and right atrial pressure (p < 0.05) compared with nonstimulated values. The highest LVP values were obtained with R-R intervals long enough to allow an adequate LV filling. We conclude that dynamic cardiomyoplasty provides an appropriate recovery in this animal model of atrial fibrillated heart failure. Cardiomyoplasty is an appropriate procedure for cardiac assist when R-R intervals allow an adequate LV filling.

Non-invasive assessment of systemic elastic behaviour in hypertensive patients: analysis of possible determinants.

Knowledge about the viscoelastic behaviour of the arterial wall has been proved to have physiological importance and clinical usage. Our purpose was to study the changes of the systemic arterial wall's elastic properties non-invasively, in patients with established essential and with borderline hypertension, and to evaluate its possible determinants. Three groups of normotensive, borderline and established essential hypertensive patients were evaluated. Arterial pulse wave velocity (PWV) was measured and arterial compliance (Cm) was derived in all patients. Pulse wave velocity was obtained from the pressure values of digitized carotid and radial arteries. Arterial compliance (Cm = dD/dP with P pressure and D diameter) was calculated using a formula derived from the Bramwell and Hill equation: Cm = (1,334 x D)/(2 rho x PWV2), where for D humeral diameter was used as measured by high resolution echograph, and rho is the blood density (rho = 1.06). Pulse wave velocity was significantly higher in established essential hypertensive patients with respect to normotensive patients (p < 0.05). Arterial compliance was significantly diminished in established and in borderline hypertensive patients with respect to normotensive patients (p < 0.05), which implies early alterations in hypertensive cardiovascular disease. Multiple regression analysis of the cofactors showed that age and diastolic pressure are independent determinants of Cm. Impairment of the arterial wall's intrinsic elastic properties was demonstrated in established essential hypertension, independent of age and diastolic pressure.