World J. Surg. 22, 1029 –1033, 1998 WORLD Journal of SURGERY © 1998 by the Socie ´te ´ Internationale de Chirurgie Short-term Outcome and Predictors of Adverse Events following Pulmonary Thromboendarterectomy Timothy B. Gilbert, M.D., 1 Sean P. Gaine, M.D., 2 Lewis J. Rubin, M.D., 2 Alejandro J. Sequeira, M.D. 3 1 Department of Anesthesiology, University of Maryland School of Medicine, Room S11-C10, 22 South Greene Street, Baltimore, Maryland 21201-1595, USA 2 Department of Medicine, University of Maryland School of Medicine, 22 South Greene Street, Baltimore, Maryland 21201-1595, USA 3 Department of Surgery, University of Maryland School of Medicine, 22 South Greene Street, Baltimore, Maryland 21201-1595, USA Abstract. Pulmonary complications including hypoxemia, right heart failure, and prolonged ventilation may follow pulmonary thromboendar- terectomy (PTE) performed via cardiopulmonary bypass (CPB) with deep hypothermic circulatory arrest. Seventeen adult patients have undergone PTE at the University of Maryland Medical System during the preceding 3 years. From these patients, clinical and hemodynamic parameters were tabulated pre-CPB, post-CPB, at admission to the intensive care unit (ICU), and prior to discontinuation of invasive monitoring in the ICU. Data on anthropometric variables, survival, and times of extracorporeal circulation, mechanical ventilation, and hospital stay were also collected. The mean values for pulmonary arterial systolic and diastolic pressures and pulmonary vascular resistance (PVR) decreased significantly from pre-CPB values after PTE (all p < 0.05). Mild mixed acidosis present at ICU admission resolved prior to discharge (p  0.002). The length of mechanical ventilation time was positively correlated with the absolute post-CPB PVR and negatively correlated with the relative change in central venous pressure (CVP) from pre-CPB to post-CPB values (r  0.75, p  0.037). Of the pre-CPB anthropometric variables, only body mass index was significantly higher in nonsurvivors (p  0.037). Pulmo- nary artery pressures and vascular resistance fall significantly after PTE. A lower post-CPB PVR and a relatively decreased (i.e., from pre-CPB values) CVP predict reduced length of postoperative ventilation but not of the hospital stay. Mortality appears increased in patients with a large body habitus. Chronic thromboembolic pulmonary hypertension (CTEPH) is an infrequent, but serious, sequela of pulmonary embolism resulting from critical occlusion of the central pulmonary arteries by organized thrombus. Pulmonary thromboendarterectomy (PTE) can dramatically reduce elevated pulmonary pressures, restore right ventricular function, relieve hypoxemia, and improve exer- cise tolerance when performed successfully in highly selected patients [1]. To provide a clear surgical field, however, endarter- ectomy of the pulmonary artery usually necessitates the use of cardiopulmonary bypass with deep hypothermic circulatory arrest (DHCA). Depending on the severity of preexisting pulmonary hypertension and right heart dysfunction, morbidity and mortality following PTE can be high (up to 22%–24% mortality in previ- ously reported series [2, 3]). Prolonged mechanical ventilation, intensive care, and hospitalization frequently follow PTE. With fewer than 1000 PTE procedures having been performed to date worldwide [4], both surgical techniques and perioperative medical management are still evolving. We reviewed the effect of PTE on systemic and pulmonary hemodynamics and short- term (i.e., in-hospital) outcome in patients undergoing the procedure at the University of Maryland Medical System since 1994. Materials and Methods All patients presenting for PTE were included in a retrospective chart review, including medical, operative, and nursing records. Preoperative anthropometric and historical data were obtained for each patient. Perioperative monitoring included radial and thermodilution/oximetric pulmonary artery catheters, a multilead electrocardiogram, measurement of nasopharyngeal and bladder temperatures, pulse oximetry, and transesophageal echocardiog- raphy. Hemodynamic and laboratory parameters were collected before and after the induction of general anesthesia, after sepa- ration from cardiopulmonary bypass (CPB), upon arrival to the intensive care unit (ICU), and immediately before discontinuation of invasive monitoring in the cardiothoracic ICU. Systemic (SVR) and pulmonary (PVR) vascular resistances were derived from measurements of cardiac output (CO), and systemic, pulmonary, and central venous (CVP) pressures. The alveolar–arterial oxygen gradient (Aa) was derived from measurements of arterial blood gases and fraction of inspired oxygen (= 100% for all pre- and post-CPB determinations, 50%–100% for ICU measurements) [5]. Times for length of CPB, aortic cross-clamping, DHCA, postoperative ventilation, and hospital stay (both total and post- operative) were also tabulated. Statistical analyses using one-way repeated measures ANOVA and multiple linear regression were performed to test for significant differences and detect any correlations, respectively, where adequate power existed among the various measure- ments. A t-test was used to detect differences between survival outcome groups. Correspondence to: T.B. Gilbert, M.D.