We have studied our experience since 1988 with 31 patients who required a mechanical circulatory bridge to transplantation and also had biventricular failure (mean right ventricular ejection fraction 11.8%) to better define the need for biventricular or total artificial heart support versus univentricular support. Clinical factors including preoperative inotropic need, fever without detectable infection, diffuse radiographic pulmonary edema, postoperative blood transfusion, and right ventricular wall thickness were compared with hemodynamic parameters including cardiac index, right ventricular ejection fraction, central venous pressure, mean pulmonary arterial pressure, and total pulmonary resistance for ability to predict need for mechanical or high-dose inotropic support for the right ventricle. Patients were grouped according to need for right ventricular support after left ventricular-assist device implantation: none (group A, 14) inotropic drugs (group B1, 7), and right ventricle mechanical support (group B2, 10). There were no differences in preimplantation hemodynamic variables. Groups B1 and B2 had significantly lower mixed venous oxygen saturation (39.2% vs 52.5% in group A; p < 0.001), greater level of inotropic need (p < 0.02), greater impairment of mental status, and lower ratio of right ventricular ejection fraction to inotropic need (0.37 vs 0.56 for group A; p < 0.02) before left ventricular-assist device implantation. A significant discriminator between groups B1 and B2 was the presence of a fever without infection within 10 days of left ventricular-assist device implantation (43% in group B1 vs 70% in group B2). Group B2 had more patients with preimplantation pulmonary edema seen on chest radiography and a greater requirement for postoperative blood transfusion (5 units of cells in group B1 vs 14.8 units in group B2. Right ventricular wall thickness at left ventricular-assist device explantation was 0.83 cm in group B2 vs 0.44 cm in group B1 (p < 0.05). Transplantation rates after bridging were 100% in group A, 71% in group B1, and 40% in group B2. Clinical factors that reflect preimplantation degree of illness and perioperative factors that result in impairment of pulmonary blood flow or reduced perfusion of the right ventricle after left ventricular-assist device implantation are now considered to be more predictive of the need for additional right ventricular support than preimplantation measures of right ventricular function or hemodynamic variables.

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Lung transplantation is associated with an immediate decrease in pulmonary artery pressures and right ventricular size and normalization of septal geometry but variable changes in right ventricular function. Continued depression of right ventricular fractional area change may be a potential marker of poor outcome.

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BACKGROUND Pressure-volume relations have been established as useful measures of left ventricular (LV) performance. Application of these methods to the intraoperative setting have been limited because of difficulties acquiring LV volume data. Transesophageal echocardiographic automated border detection can measure LV cross-sectional area as an index of volume, which can be coupled with pressure data to construct pressure-area loops on-line. The purpose of this study was to evaluate intraoperative LV performance in patients undergoing coronary bypass surgery before and immediately after cardiopulmonary bypass using on-line pressure-area relations. METHODS AND RESULTS Studies were attempted in 13 consecutive patients. Simultaneous measures of LV cross-sectional area, LV pressure, and electromagnetic flow probe-derived aortic flow recorded on a computer work station interfaced with the ultrasound system. Pressure-area loops were compared with simultaneous pressure-volume loops constructed from pressure and flow data during inferior vena caval occlusions before and after bypass. Pressure-volume calculations (end-systolic elastance, maximal elastance, and preload-recruitable stroke work) were then applied to pressure-area loops with area substituted for volume data. Changes in stroke force from pressure-area loops were closely correlated with changes in estimates of stroke work from pressure-volume loops for individual patients before bypass (r = .99 +/- .03, SEE = 5 +/- 2%, n = 10) and after bypass (r = .96 +/- .05, SEE = 5 +/- 2%, n = 9). Pressure-area estimates of end-systolic elastance, maximal elastance, and preload-recruitable stroke force decreased significantly from before to after cardiopulmonary bypass in the 7 patients with paired data sets. Load-dependent measures of LV function (stroke volume, cardiac output, and fractional area change) were unchanged after surgery in these same patients. CONCLUSIONS Intraoperative pressure-area loops may be acquired and displayed on-line using transesophageal echocardiographic automated border detection and readily analyzed in a manner similar to pressure-volume loops. LV performance was depressed immediately after cardiopulmonary bypass compared with before. On-line pressure-area relations may be clinically useful to assess LV performance in patients undergoing cardiac surgery in whom load and contractility may be expected to vary rapidly.