Bicuspid aortic valves are associated with aortic dilatation out of proportion to coexistent valvular lesions.

BACKGROUND: Bicuspid aortic valves (BAVs) are associated with premature valve stenosis, regurgitation, and ascending aortic aneurysms. We compared aortic size in BAV patients with aortic size in control patients with matched valvular lesions (aortic regurgitation, aortic stenosis, or mixed lesions) to determine whether intrinsic aortic abnormalities in BAVs account for aortic dilatation beyond that caused by valvular hemodynamic derangement alone. METHODS AND RESULTS: Diameters of the left ventricular outflow tract, sinus of Valsalva, sinotubular junction, and proximal aorta were measured from transthoracic echocardiograms in 118 consecutive BAV patients. Annular area was measured by planimetry, and BAV eccentricity was expressed as the ratio of the right leaflet area to the total annular area. Seventy-seven control patients with tricuspid aortic valves were matched for sex and for combined severity of regurgitation and stenosis. BAV patients (79 men and 39 women, aged 44.1+/-15.5 years) had varying degrees of regurgitation (84 patients [71%]) and stenosis (48 patients [41%]). Within the bicuspid group, multivariate analysis demonstrated that aortic diameters increased with worsening aortic regurgitation (P:<0.001) and advancing age (P:<0.05) but not with the severity of aortic stenosis. BAV patients had larger aortic diameters than did control patients at all ascending aortic levels measured (P:<0.01), despite advanced age in the control patients. CONCLUSIONS: Aortic dimensions are larger in BAV patients than in control patients with comparable degrees of tricuspid aortic valve disease. Although more severe degrees of aortic regurgitation are associated with aortic dilatation in BAV patients, intrinsic pathology appears to be responsible for aortic enlargement beyond that predicted by hemodynamic factors.

Structural determinants of aortic regurgitation in type A dissection and the role of valvular resuspension as determined by intraoperative transesophageal echocardiography.

Disruption of the aortic root by dissection often produces significant aortic regurgitation (AR). Resuspension of the native valve usually reestablishes competence. The mechanisms of this complex process are poorly understood. We used intraoperative transesophageal echocardiography to characterize the in vivo aortic root structure of type A aortic dissection and the changes brought about by native valve resuspension. Intraoperative transesophageal echocardiograms were obtained from 34 patients with type A dissection and aortic resuspension between January 1990 and April 1997. The severity of AR, aortic root diameter, circumference of the aortic annulus, percentage of the annulus dissected, and presence of leaflet prolapse were assessed in multiple planes. Preoperatively, AR of varying degree was present in 25 patients (73%). Multivariate analysis revealed that preoperative AR was most related to percentage of the annulus dissected (p<0.0001) and less related to root diameter (p<0.01). Leaflet prolapse was predicted by percent aortic annulus dissected (p <0.0001). After resuspension, annular dissection and leaflet prolapse were no longer present. Postoperative AR was significantly decreased from preoperative AR (p<0.0001) and was considered trace to mild. Although postoperative root diameter and annular circumference decreased (p<0.001), individual reductions in AR did not correlate with individual changes in root diameter or annular circumference. The degree of dissection of the valve annulus is the most significant determinant of leaflet prolapse and AR severity. Overall size of the aortic root also contributes to AR. Surgical resuspension significantly decreases root size, but its primary benefit is restoration of the structural integrity of the aortic annulus.

Tetracycline pleurodesis--associated acute renal failure.

Chemical pleurodesis is a frequently performed procedure for pneumothorax and effusion and significant adverse effects are unusual. We present a previously unreported case of acute renal failure associated with tetracycline pleurodesis. Recent studies have shown that intrapleural drug administration may lead to therapeutic serum levels. Systemic toxic drug effects may therefore be noted with chemical pleurodesants such as tetracycline. Alternative methods of pleurodesis should always be considered if a sensitivity or metabolic abnormality is suspected.

Mediastinoscopic subtotal removal of mediastinal cysts.

STUDY OBJECTIVE: Evaluate the use of mediastinoscopy in the surgical diagnosis and treatment of mediastinal cystic masses in adults. DESIGN: Case reports and literature review. SETTING: Academic department of surgery. PATIENTS: Three consecutive adults with mediastinal masses identified on plain radiographs and CT. INTERVENTIONS: Operative mediastinoscopy. MEASUREMENTS AND RESULTS: All patients were successfully treated with removal of cyst wall, establishment of diagnosis, and same-day hospital discharge. CONCLUSIONS: Simple mediastinoscopic removal of mediastinal cysts offers the same potential for diagnosis and treatment as more conventional methods, with a potential for less morbid and more cost-effective care.

Flow dynamics of peripheral venous catheters during extracorporeal membrane oxygenation with a centrifugal pump.

Extracorporeal membrane oxygenation uses peripherally placed cannulas and a streamlined circuit without a venous reservoir. This study tests the flow dynamics of venous catheters connected without a reservoir directly to a centrifugal pump. During in vitro testing, a 30 cm segment of collapsible tubing interposed between the reservoir and pump simulates the vein. In five sheep, flow was measured between catheters placed in the right atrium and inferior vena cava from peripheral sites. Catheter tip design (four types) does not affect flow within a simulated vein in vitro. Maximum pump flow is independent of filling pressures (6 to 21 mm Hg) in vitro and in vivo when the catheter tip is in a tank reservoir or the right atrium. However, when the catheter tip is within a collapsible segment or in the inferior vena cava, maximal flow is significantly influenced by filling pressure (6 to 18 mm Hg) and by the ratio of catheter outer diameter to venous diameter. At all filling pressures, maximal flow in vivo is significantly reduced when this ratio is greater than 0.5. During extracorporeal membrane oxygenation, central venous pressure and catheter/vein ratio, not catheter size alone, control flow through peripheral venous catheters.

Left ventricular mechanics of ejecting, postischemic hearts during left ventricular circulatory assistance.

We measured the effects of left ventricular circulatory assistance on ventricular mechanics of ejecting sheep hearts before and after global ischemia. Flows from left atrium to femoral artery ranged between 20 and 100 ml/kg/min during circulatory assistance. In preischemic, ejecting hearts increasing flow through the left ventricular assist device progressively decreased stroke volume, end-diastolic volume, and circumferential systolic wall stress, but only slightly decreased end-systolic volume. In postischemic, ejecting hearts left ventricular assistance progressively and substantially decreased both end-diastolic volume and end-systolic volume; at high flows, end-systolic volume returned to the normal range of preischemic hearts. High flows through the assist device also shifted end-systolic points of pressure-volume loops leftward and increased the stroke work/end-diastolic volume ratio in ejecting postischemic hearts; these observations raise the possibility that left ventricular circulatory assistance acutely improves myocardial contractility of postischemic hearts.

Bilateral versus single lung transplantation for chronic obstructive pulmonary disease.

OBJECTIVE: Traditionally, despite ventilation/perfusion mismatch, single lung transplantation has been the mainstay for end-stage chronic obstructive pulmonary disease. We tested the hypothesis that bilateral sequential lung transplantation has better short- and intermediate-term results than single lung transplantation for chronic obstructive pulmonary disease. METHODS: One hundred twenty-six consecutive lung transplants have been performed from November 1991 to March 1996. Seventy-six have been for chronic obstructive pulmonary disease. The diagnosis of this disease includes emphysema (80.3%), alpha 1-antitrypsin deficiency (9.2%), lymphangioleiomyomatosis (7.9%), and obliterative bronchiolitis (2.6%). Twenty-nine transplants have been bilateral and 47 have been single. Mean age was 55.3 for patients having single lung transplantation and 48.8 for those having bilateral lung transplantation (p = 0.001). The distribution of the diagnoses was similar between the two groups. At 6 months, there were 29 survivors of single lung transplantation and 20 survivors of bilateral lung transplantation, with complete data for evaluation. Pulmonary function tests and 6-minute walk tests were evaluated at a mean of 15.4 and 12.8 months after transplantation, respectively. RESULTS: Sixty-day mortality was 21.3% for single lung transplantation versus only 3.45% for bilateral lung transplantation (p = 0.03). Additionally, Kaplan-Meier analysis revealed 1- and 2-year survivals of 71.1% and 63.3% for single lung transplantation versus 90% and 90% for bilateral lung transplantation, respectively. Multiple major morbidities were analyzed. Primary graft failure was significantly reduced in the bilateral group (p = 0.049). Both 6-minute walk tests and forced expiratory volume in 1 second were improved from baseline by both single and bilateral lung transplantation (p = 0.001). CONCLUSIONS: Bilateral lung transplantation improves forced expiratory volume in 1 second and 6-minute walk tests significantly over single lung transplantation (p < 0.0001). Both perioperative mortality and Kaplan-Meier survival (to 3 years) are significantly improved when bilateral rather than single lung transplantation is used for chronic obstructive pulmonary disease in our series (p < 0.05). This is probably the result of significantly reduced primary graft failure.

Bilateral lung volume reduction surgery for advanced emphysema. A comparison of median sternotomy and thoracoscopic approaches.

STUDY OBJECTIVES: To compare short-term outcomes following bilateral lung volume reduction surgery performed by median sternotomy (MS) and video-assisted thoracoscopic surgery (VATS). METHODS: Bilateral lung volume reduction surgery was performed by MS in 80 patients and by VATS in 40. All patients underwent preoperative assessment with pulmonary function testing, arterial blood gas determination, and 6-min walk test (6MWT). Pulmonary function testing and 6MWT were repeated at 3 to 6 months postoperatively. RESULTS: The mean age of the VATS group was lower than that of the MS group (59.3 +/- 9.4 vs 62.4 +/- 6.9 years; p = 0.001), but there were no differences in baseline functional parameters of disease severity (FEV1, FVC, residual volume [RV], arterial PCO2, or 6MWT). All patients in both groups were extubated at the completion of surgery, but 17.5% of patients in the MS group and 2.5% in the VATS group (p = 0.02) subsequently required reintubation at some point during the postoperative course. Thirty-day operative mortality was 4.2% for the MS group and 2.5% for the VATS group (p = not significant). However, total in-hospital mortality was 13.8% for the MS group, while it remained 2.5% for the VATS group (p = 0.05). Mortality was largely confined to patients 65 years of age or older. There was no significant difference in duration of air leaks or length of hospital stay between the two groups. Functional outcomes achieved with the two techniques were similar. Specifically, there was no difference between the two groups in mean postoperative FEV1, FVC, RV, or 6MWT, or in the magnitude of change in these parameters over preoperative values. CONCLUSIONS: Bilateral lung volume reduction surgery performed by either MS and VATS approaches leads to similar improvements in pulmonary function and exercise tolerance. VATS is associated with a significantly lower incidence of respiratory failure and a trend toward decreased in-hospital mortality and may be the preferred technique, particularly for high-risk patients.

Primary graft failure following lung transplantation.

STUDY OBJECTIVES: To determine the incidence of primary graft failure (PGF) following lung transplantation, assess possible risk factors, and characterize its effect on outcomes. METHODS: Retrospective review of 100 consecutive patients undergoing lung transplantation at the University of Pennsylvania Medical Center. Fifteen patients meeting diagnostic criteria for PGF (PGF+ group) were compared with 85 patients without this complication (PGF- group). RESULTS: The incidence of PGF was 15%. There was no significant difference in age, sex, underlying pulmonary disease, preoperative pulmonary artery systolic pressure, type of transplant, allograft ischemic times, use of cardiopulmonary bypass, or use of postoperative prostaglandin E1 infusion between the PGF+ and PGF- groups. Induction therapy with antilymphocyte globulin was used less frequently in the PGF+ group (p<0.005). Duration of mechanical ventilatory support was 36+/-43 days vs 4+/-6 days for the PGF+ and PGF- groups, respectively (p<0.0001). Hospital stay was significantly longer in the PGF+ group, averaging 75+/-105 days, compared with 27+/-38 days in the PGF group (p<0.005). One-year actuarial survival for the PGF+ group was only 40% compared with 69% for the PGF- group (p<0.005). Five of the six PGF+ survivors were ambulatory by 1 year; three were completely independent while two continued to require assistance with activities of daily living. Six-minute walk test distance among the ambulatory patients averaged 883+/-463 feet (range, 200 to 1,223 feet) compared with 1513+/-424 feet for the PGF- group (p<0.005). Among the subset of survivors who underwent single lung transplantation for COPD, the mean percent predicted FEV1 at 1 year was 43% for the PGF+ group and 55% for the PGF- groups, but this difference was not statistically significant. CONCLUSIONS: PGF is a devastating postoperative complication, occurring in 15% of patients in the current series, and it is associated with a high mortality rate, lengthy hospitalization, and protracted and often compromised recovery among survivors.

Myocardial oxygen utilization after reversible global ischemia.

We tested in 20 sheep the hypothesis that oxygen consumption increases after reversible, global myocardial ischemia. Left ventricular oxygen consumption before and after 25 minutes of warm (37 degrees C) global ischemia was linearly related to a function (integral) of left ventricular circumferential systolic wall stress, altered by changing afterload. The relation is expressed in the two regression equations: LVO2 (preischemic) = 1.06.SSI + 16.8 (n = 129; r = 0.79); LVO2 (postischemic) = 4.35.SSI + 5.6 (n = 89; r = 0.65). The fourfold increase in slope (4.35 versus 1.06) indicates (p = 0.0001) a massive increase of oxygen consumption in postischemic, globally "stunned" myocardium. The inferences are that globally stunned myocardium causes severe impairment of oxygen utilization efficiency, and increased vulnerability to further ischemia if coronary vessels are diseased.

Detection of stroke during cardiac operations with somatosensory evoked responses.

OBJECTIVES: The objectives of this study were to determine if monitoring of intraoperative somatosensory evoked potentials could be used to detect stroke during cardiac operations and to establish indicators of cerebral ischemia based on changes in these potentials. METHODS: Twenty-five patients undergoing cardiac operations underwent preoperative and postoperative neurologic examinations as well as intraoperative recording of somatosensory evoked potentials. Detailed analysis of the waveforms of these potentials was performed. RESULTS: Two of the 25 patients had intraoperative strokes. These patients and only these patients had changes in their somatosensory evoked potentials during the operation suggesting cerebral ischemia. The unilateral disappearance of the cortical somatosensory evoked potential waves correlated significantly with the clinical outcome of stroke (p < 0.004). Ischemic changes were detected in real time and were related to the removal of the aortic crossclamp in one patient and to the initiation of cardiopulmonary bypass in the other. CONCLUSIONS: Somatosensory evoked potentials can detect intraoperative stroke during cardiac operations. Acute, unilateral decreases in amplitude of the cortical potential are more useful than changes in latency in detecting intraoperative stroke.

Characteristics and outcomes of patients with sarcoidosis listed for lung transplantation.

STUDY OBJECTIVES: To characterize the course of patients with advanced sarcoidosis who have been listed for lung transplantation and to identify prognostic factors for death while they are on the waiting list. DESIGN: Retrospective cohort study. SETTING: Tertiary-care university hospital. PATIENTS: Forty-three patients with sarcoidosis who have been listed for lung transplantation at the University of Pennsylvania Medical Center. METHODS: A multivariable explanatory analysis using a Cox proportional hazards model was performed to determine risk factors that are independently associated with mortality while patients await transplantation. RESULTS: Twenty-three of the 43 patients (53%) died while awaiting transplantation. The survival rate of listed patients (as determined by the Kaplan-Meier method) was 66% at 1 year, 40% at 2 years, and 31% at 3 years. In a univariate analysis, the following factors were significantly associated with death on the waiting list: PaO(2) < or = 60 mm Hg (relative risk [RR], 3.4; 95% confidence interval [CI], 1.2 to 9.3); mean pulmonary artery pressure > or = 35 mm Hg (RR, 3.2; 95% CI, 1.1 to 9.5); cardiac index < or = 2 L/min/m(2) (RR, 2.8; 95% CI, 1.2 to 6.6), and right atrial pressure (RAP) > or = 15 mm Hg (RR, 7.6; 95% CI, 3.0 to 19.3). Multivariable analysis revealed that RAP > or = 15 mm Hg was the only independent prognostic variable (RR, 5.2; 95% CI, 1.6 to 16.7; p = 0.006). Twelve patients underwent lung transplantation. Survival after transplantation determined by the Kaplan-Meier method was 62% at both 1 and 2 years, and 50% at 3 years. CONCLUSIONS: Patients with advanced sarcoidosis awaiting lung transplantation have a high mortality rate with a median survival of < 2 years. Mortality is most closely linked to elevated RAP. While earlier referral may diminish the mortality rate of patients on the waiting list for transplantation, further improvements in posttransplantation outcomes will be necessary to ensure that this procedure truly bestows a survival benefit.

Effect of volume reduction on lung transplant timing and selection for chronic obstructive pulmonary disease.

BACKGROUND: End-stage chronic obstructive pulmonary disease has traditionally been treated with lung transplantation. For 2 years, our lung transplantation program has placed patients with appropriate criteria for lung transplantation and volume reduction into a prospective management algorithm. These patients are offered the lung volume reduction option as a "bridge" to "extend" the eventual time to transplantation. We examine the results of this pilot program. METHODS: From October 11, 1993, to April 17, 1997, 31 patients were evaluated for lung transplantation who also had physiologic criteria for volume reduction (forced expiratory volume in 1 second < or = 25%; residual volume > 200%; significant ventilation/perfusion heterogeneity). All patients completed 6 weeks of pulmonary rehabilitation and then had baseline pulmonary function and 6-minute walk tests. These patients were then offered volume reduction as a "bridge" and were simultaneously listed for transplantation. Postoperatively, these 31 patients were then divided into two groups: Those with satisfactory results at 4 to 6 months after volume reduction and those with unsatisfactory results. Volume reduction was performed through a video thoracic approach in 87% of the patients and bilateral median sternotomy in the remaining 13%. The condition of the patients was monitored after the operation with repeated pulmonary function tests and 6-minute walk tests at 3-month intervals. RESULTS: Twenty-four of 31 patients (77.4%) had primary success (at 4 to 6 months) results after lung volume reduction and 7 patients (22.6%) had primary failure, including 1 patient who died in the perioperative period (3.2%). Four patients (16.7%) from the primary success cohort had significant deterioration in their pulmonary function during intermediate-term follow-up and were then reconsidered for lung transplantation. Two of them have subsequently undergone transplantation with good postoperative pulmonary function results. Interestingly, three patients had alpha 1-antitrypsin deficiency; two had a poor outcome of lung volume reduction and primary failure. CONCLUSIONS: Lung volume reduction in these patients is safe. Seventy-seven percent of otherwise suitable candidates for lung transplantation achieved initial good results from volume reduction and were deactivated from the list (placed on status 7). Most patients entering our prospective management algorithm have either significantly delayed or completely avoided lung transplantation after volume reduction. Lung volume reduction has substantially affected the practice, timing, and selection of patients for lung transplantation. Our waiting list now has a reduced percentage of patients with a diagnosis of chronic obstructive pulmonary disease compared with 3 years ago. Our experience suggests that lung volume reduction may be limited as a "bridge" in alpha 1-antitrypsin deficiency.

Comparison of short-term functional outcomes following unilateral and bilateral lung volume reduction surgery.

STUDY OBJECTIVES: To compare short-term functional outcomes following unilateral and bilateral lung volume reduction surgery (LVRS) performed in patients with advanced emphysema. METHODS: LVRS was performed unilaterally in 32 patients and bilaterally in 119 patients. Pulmonary function testing and 6-min walk test (6MWT) were performed preoperatively and repeated at 3 to 6 months postoperatively. RESULTS: Bilateral LVRS was associated with increased in-hospital mortality (10% vs 0%, p<0.05) and a higher incidence of postoperative respiratory failure (12.6% vs 0%; p<0.05) compared with unilateral LVRS. There was no significant difference in duration of air leaks between unilateral and bilateral groups, but the mean hospital stay was significantly longer following bilateral LVRS (21.1+/-32.0 days vs 14.2+/-14.0 days; p<0.05). Preoperatively, there was no significant difference between the unilateral and bilateral groups with respect to FEV1, FVC, residual volume, or 6MWT distance. However, for all of these parameters, the magnitude of improvement was significantly greater following bilateral LVRS. Notably, the magnitude of improvement in each parameter following unilateral LVRS exceeded half that following bilateral LVRS, suggesting that functional outcomes after the unilateral procedure were disproportionate to the amount of tissue resected. Serial functional assessment of seven patients undergoing staged unilateral procedures (two unilateral procedures separated in time by at least 3 months) demonstrated somewhat unpredictable responses; failure to achieve a favorable response to the initial procedure did not necessarily portend a similar outcome with the contralateral side, and vise versa. CONCLUSIONS: Bilateral LVRS produces a greater magnitude of short-term functional improvement than does the unilateral procedure and should be considered the procedure of choice for most patients. Unilateral LVRS should be reserved for patients in whom factors contraindicating entrance into one hemithorax exist.

Bronchogenic carcinoma complicating lung transplantation.

BACKGROUND: Malignancy is a well-recognized complication of solid-organ transplantation. Although a variety of malignancies have been reported in lung transplant recipients, a paucity of information exists regarding the incidence and clinical course of bronchogenic carcinoma in this patient population. METHODS: We conducted a retrospective cohort study of our lung transplant experience at the University of Pennsylvania. RESULTS: We identified 6 patients with bronchogenic carcinoma detected at the time of, or developing after, transplantation. The incidence of bronchogenic carcinoma was 2.4%. All patients with lung cancer had a history of smoking, with an average of 79 +/- 39 pack-years. A total of 5 patients had chronic obstructive pulmonary disease, and 1 had idiopathic pulmonary fibrosis. Lung cancers were all of non-small-cell histology and first developed in native lungs. Three patients had bronchogenic carcinoma at the time of surgery. The remaining 3 patients were diagnosed between 280 and 1,982 days post-transplantation. Of the 6 patients, 4 presented with a rapid course suggestive of an infectious process. The 1- and 2-year survival rates after diagnosis were 33% and 17%, respectively. CONCLUSION: Lung transplant recipients are at risk for harboring or developing bronchogenic carcinoma in their native lungs. Rapid progression to locally advanced or metastatic disease commonly occurs, at times mimicking an infection. Bronchogenic carcinoma should be considered in the differential diagnosis of pleuroparenchymal processes involving the native lung.

Anterior axillary muscle-sparing thoracotomy for lung transplantation.

We have been using an anterior axillary muscle-sparing thoracotomy to perform single-lung transplantation in patients with chronic obstructive pulmonary disease. The incision allows excellent exposure and may lead to improved chest wall and shoulder girdle mechanics, which may allow for a faster recovery. This incision has become our preferred approach in patients with chronic obstructive pulmonary disease requiring single-lung transplantation who have not had a previous ipsilateral thoracic operation.

Complications of thoracoscopy.

Although thoracoscopy has been a part of thoracic surgical practice for many years, the advent of video-assisted techniques has greatly expanded the indications and the uses of this procedure. Where previously thoracoscopy was performed mainly for diagnostic purposes, it now has assumed a major role in the therapy of chest pathology. In an attempt to inject a modicum of perspective into the tremendous enthusiasm that has accompanied the meteoric rise of video-assisted thoracoscopy, we have reviewed the experience at the Hospital of the University of Pennsylvania accumulated over the 1-year period from December 1991 to December 1992, specifically looking at complications resulting from the thoracoscopic procedure. During this period we performed 266 thoracoscopic procedures with no deaths. The overall incidence of complications was 10%, with the most prevalent complication being prolonged air leak (3.7%). There were five superficial wound infections (1.9%) and 5 patients who bled significantly enough to require either transfusion or reoperation, or both. In 11 patients (4.1%), the proposed thoracoscopic procedure could not be completed as planned, and a thoracotomy was required. The incidence of complications is certainly acceptable and similar to that seen after thoracotomy, although overall hospital stay is shorter and patients seem to have less pain and return to normal activity sooner. One would expect the incidence of complications to further decrease as surgeons acquire more experience with this significant modification and improvement of an old technique.

Relationship between total mechanical energy and oxygen consumption in the stunned myocardium.

We studied the relationship between left ventricular oxygen consumption (LVVO2) and total ventricular mechanical energy production as determined by calculation of the systolic pressure-volume area (P-VA) before and after 25 minutes of warm ischemia in 7 sheep. We compared the relationship between LVVO2 and P-VA with the relationships between LVVO2 and stroke work and between LVVO2 and the systolic stress integral. Using the methods presented, P-VA can be measured in vivo (n = 123) in both preischemic and postischemic hearts. Ischemia increases the slopes of the relationship between LVVO2 and P-VA and between stroke work and the systolic stress integral, and reduces the oxygen utilization efficiency of stroke work to less than 2%. Coefficients of determination for the relationship between LVVO2 and P-VA are, in general, higher than those between LVVO2 and either stroke work or the systolic stress integral. We conclude that systolic P-VA can be measured in vivo using recently developed methods and that it is applicable to postischemic "stunned" hearts. Because P-VA and LVVO2 can be converted into identical energy units, calculation of P-VA permits calculation of myocardial oxygen utilization efficiency.

Loss of alpha-v integrin expression and recurrence in node-negative lung carcinoma.

BACKGROUND: Despite "curative" resection, metastases develop in many patients with node-negative (N0) non-small cell lung carcinoma. Alternative biologic markers for this tumor would be useful. Integrins are cell adhesion molecules that are thought to be important in tumor progression, and expression of these molecules previously has been shown to be altered in non-small cell lung carcinoma. We evaluated alterations in integrin expression and clinical outcome. METHODS: Immunohistochemical staining of tumor specimens was performed, and clinical data were reviewed retrospectively. RESULTS: Data were complete for 42 patients. Half of all patients (21/42) and 9 of 26 patients with negative nodes experienced tumor recurrence during follow-up. Neither histologic type nor tumor differentiation status correlated with recurrence. However, loss of the alpha v integrin subunit was associated significantly with recurrence in the N0 group. Seventy-five percent of patients with negative nodes who exhibited recurrence lost alpha v expression, compared with only 10% of patients with negative nodes who did not exhibit recurrence (p = 0.012). Alterations of other integrin subunits did not correlate significantly with prognostic follow-up variables. CONCLUSIONS: Loss of alpha v expression may serve as a marker for patients with node-negative non-small cell lung carcinoma who are at high risk for recurrence, potentially directing additional therapies.

Effect of circulatory assist devices on stunned myocardium.

We studied the effects of mechanical circulatory assist devices on left ventricular oxygen consumption, the integrals of systolic left ventricular wall stress (SSI), and end-systolic elastance (Ees) in 8 sheep after 25 minutes of global ischemia. Extracorporeal membrane oxygenation at 35 mL/kg/min, intraaortic balloon counterpulsation, and an intraaortic double-balloon pump were studied alone or in combination. Left ventricular oxygen consumption, SSI, and Ees were measured before and during mechanical circulatory assistance. Left ventricular oxygen consumption was calculated from transit-time measurements of left main coronary artery blood flow and fiberoptic measurements of coronary sinus blood oxygen saturation. Three pairs of sonomicrometry crystals placed across three orthogonal ventricular axes were used to calculate instantaneous ventricular volumes and pressure-volume loops from which the SSI data were derived. The Ees was measured using a new single-beat aortic occlusive method. Extracorporeal membrane oxygenation alone increased SSI and did not change Ees in postischemic poorly contracting hearts. Intraaortic balloon counterpulsation alone significantly reduced SSI and increased Ees. The combination of extracorporeal membrane oxygenation and either the intraaortic balloon pump or the intraaortic double-balloon pump reduced SSI, increased Ees, and reduced left ventricular oxygen consumption. In postischemic dilated, poorly contracting hearts, the combination of extracorporeal membrane oxygenation and intraaortic balloon counterpulsation has important advantages over extracorporeal membrane oxygenation alone.