Pulmonary thromboendarterectomy combined with other cardiac operations: indications, surgical approach, and outcome.

BACKGROUND: Patients with pulmonary hypertension due to chronic thromboembolic disease benefit from pulmonary thromboendarterectomy. A subset of these patients present with concomitant coronary or valvular disease. METHODS: From July 1990 to July 2000, 90 patients (68 males, 22 females, mean age 68 years) with pulmonary vascular resistance (PVR) ranging from 297 to 2261 dynes x sec x cm(-5) underwent pulmonary thromboendarterectomy in conjunction with coronary bypass grafting (59 patients), coronary artery bypass grafting/foramen ovale closure (24 patients), tricuspid annuloplasty (3 patients), mitral valve repair (2 patients), and aortic valve replacement (2 patients). The perioperative and hemodynamic outcomes of these patients were compared with the cohort of 1,100 isolated pulmonary thromboendarterectomies performed at our institution during this time. RESULTS: Overall perioperative survival (93.3%; 84 of 90 patients) and mean diminution in PVR (521 dynes x sec x cm(-5)) for patients undergoing combined operations were similar to those undergoing pulmonary thromboendarterectomy alone (94.2% survival; 1034 of 1100 patients; 547 dynes x sec x cm(-5) mean PVR reduction). Although patients undergoing combined operations were older (mean age 68 vs 50 years, p < 0.0001), had longer hospital stays (median 14 vs 9 days), and had worse left ventricular function (mean preoperative cardiac output 3.1 vs 4.4, p < 0.0001), there was no difference in cross-clamp time, resolution of tricuspid regurgitation, or postoperative systolic function between these two groups. CONCLUSIONS: Pulmonary thromboendarterectomy for chronic thromboembolic pulmonary hypertension may be performed safely in conjunction with other cardiac operations. Older patients evaluated for pulmonary thromboendarterectomy should be screened for concomitant coronary and valvular disease.

Human angiopoietin gene expression is a marker for severity of pulmonary hypertension in patients undergoing pulmonary thromboendarterectomy.

OBJECTIVE: A consistent pathologic feature seen in lungs of patients with pulmonary hypertension from thromboembolic disease is hyperplasia of the media of pulmonary arterioles. The molecular factors responsible for these vessel wall changes are unknown. Angiopoietin-1 is a gene responsible for the formation of the media of blood vessels in utero. We hypothesized that aberrant expression of the angiopoietin-1 gene in the adult lung would be a major contributing factor in the development of pulmonary hypertension. METHODS: From April 1999 to March 2000, a total of 35 patients (18 men, 17 women, mean age 52 years) with pulmonary hypertension and pulmonary vascular resistance ranging from 407 to 2006 dynes x sec x cm(-5) underwent pulmonary endarterectomy at our institution. Before cardiopulmonary bypass, lung biopsy specimens were taken from each patient. Biopsy specimens were also obtained from 10 patients (5 women, 5 men, mean age 55 years) undergoing lung resection for causes other than pulmonary hypertension. All specimens were blindly scored by a pathologist for degree of medial hyperplasia. Quantitative reverse transcriptase-polymerase chain reaction, Western blot, and immunohistochemistry were used to quantitate angiopoietin-1 messenger RNA and protein in each sample. RESULTS: Lung specimens from all patients with pulmonary hypertension demonstrated up-regulation of angiopoietin-1 at the messenger RNA level. The degree of angiopoietin-1 transcription was directly proportional to the preoperative pulmonary vascular resistance and medial wall hyperplasia/hypertrophy in each patient. By immunohistochemistry, angiopoietin-1 protein was confined to the media of pulmonary arterioles. Lung biopsy specimens from patients without pulmonary hypertension had no detectable expression of angiopoietin-1 at the messenger RNA or protein level. CONCLUSION: Angiopoietin-1, a gene responsible for vessel development in the embryonic lung, is up-regulated in the lung parenchyma of patients with pulmonary hypertension. The level of expression of angiopoietin-1 at messenger RNA and protein levels correlates to the severity of pulmonary hypertension in patients with thromboembolic disease and serves as a target for strategies to treat this disease.

Surgical management of congenital obstruction of the left main coronary artery with supravalvular aortic stenosis.

OBJECTIVE: Stenosis of the left main coronary artery is a recognized complicating feature of supravalvular aortic stenosis. We have retrospectively identified three anatomic subtypes of left main coronary obstruction in patients with supravalvular aortic stenosis, each necessitating a distinct surgical approach. METHODS: From 1991 to 1998, 9 patients underwent surgical repair of supravalvular aortic stenosis and left main coronary stenosis. Five patients (group 1) had obstruction from near-circumferential thickening of the left main ostium, 2 patients (group 2) had restricted coronary flow due to fusion of an aortic valve leaflet to the supravalvular ridge, and 2 patients (group 3) had diffuse narrowing of the left main coronary artery. Group 1 patients were treated with patch aortoplasty encompassing the left main ostium and supravalvular aortic stenosis. Group 2 patients were treated with excision of the fused leaflet from the aortic wall and patch aortoplasty. Group 3 patients were treated with bypass grafting and aortoplasty. RESULTS: Surgical strategy was determined by coronary angiography and intraoperative assessment of coronary anatomy. There was 1 early death. All surviving patients underwent echocardiography with or without postoperative catheterization. The mean postoperative supravalvular gradient for 7 patients was 8 mm Hg (range 2-15 mm Hg). One patient required reoperation for a residual aortic gradient as a result of aortic arch involvement. No evidence of left main coronary artery stenosis was seen in groups 1 and 2; bypass grafts were patent in group 3 patients at a mean follow-up of 54.8 months. CONCLUSION: Three subtypes of left main coronary stenosis with supravalvular aortic stenosis are described. Each anatomic type mandates an individual surgical approach. Favorable surgical outcomes are achievable with each category.

The effect of PVC packaging on the acidity of 0.9% saline.

Intravenous fluids in polyvinyl chloride (PVC) packaging are known to be acidic. We proposed to determine the effect of PVC packaging on the pH of 0.9% saline solutions by comparing the predicted and measured pH of 0.9% saline equilibrated with atmospheric carbon dioxide and the measured pH of commercial solutions of 0.9% saline in PVC and polypropylene packaging. Calculation of pH was made from available physical chemistry constants and data. Measurement was made of the pH of 12 samples of prepared 0.9% saline equilibrated with atmospheric carbon dioxide. Comparison with the pH of seven commercial samples of saline in PVC packaging for intravenous use was undertaken. Further comparison was made between commercial samples of 0.9% saline in PVC or polypropylene packaging. The calculated pH of 0.9% saline was 5.61 at 20 degrees C. The median pH of the prepared samples was statistically significantly less acidic than the median pH of the PVC packaged samples for intravenous use: 5.47 vs 4.60, P < 0.05. The median pH of the PVC packaged saline was also statistically significantly more acidic than the pH of the polypropylene packaged saline: 4.62 vs 5.71, P < 0.05. The acidity of the intravenous solutions of 0.9% saline packaged in PVC was much greater than expected and is only partially explained by dissolved carbon dioxide. This acidity could be a result of packaging in PVC.

Early expression of angiogenesis factors in acute myocardial ischemia and infarction.

BACKGROUND: When the myocardium is deprived of blood, a process of ischemia, infarction, and myocardial remodeling is initiated. Hypoxia-inducible factor 1 (HIF-1) is a transcriptional activator of vascular endothelial growth factor (VEGF) and is critical for initiating early cellular responses to hypoxia. We investigated the temporal and spatial patterns of expression of the alpha subunit of HIF-1 (HIF-1alpha) and VEGF in specimens of human heart tissue to elucidate the early molecular responses to myocardial hypoxia. METHODS: Ventricular-biopsy specimens from 37 patients undergoing coronary bypass surgery were collected. The specimens were examined by microscopy for evidence of ischemia, evolving infarction, or a normal histologic appearance. The specimens were also analyzed with the reverse-transcriptase polymerase chain reaction for HIF-1alpha and VEGF messenger RNA (mRNA) expression and by immunohistochemical analysis for the location of the HIF-1alpha and VEGF proteins. RESULTS: HIF-1alpha mRNA was detected in myocardial specimens with pathological evidence of acute ischemia (onset, <48 hours before surgery) or early infarction (onset, <24 hours before surgery). In contrast, VEGF transcripts were seen in specimens with evidence of acute ischemia or evolving infarction (onset, 24 to 120 hours before surgery). Patients with normal ventricles or evidence of infarction in the distant past had no detectable levels of either VEGF mRNA or HIF-1alpha mRNA. HIF-1alpha immunoreactivity was detected in the nuclei of myocytes and endothelial cells, whereas VEGF immunoreactivity was found in the cytoplasm of endothelial cells lining capillaries and arterioles. CONCLUSIONS: An increase in the level of HIF-1alpha is an early response to myocardial ischemia or infarction. This response defines, at a molecular level, one of the first adaptations of human myocardium to a deprivation of blood. HIF-1alpha is a useful temporal marker of acutely jeopardized myocardium.

Ablation of persistent air leaks after thoracic procedures with fibrin sealant.

Prolonged air leak after thoracic procedures was successfully treated in 11 of 12 patients under local anesthesia using video thoracoscopic instillation of fibrin sealant over the site of the leak. No related complications occurred. This method should be considered an effective option for the treatment of persistent pulmonary air leaks.

Surgical management of spontaneous left main coronary artery dissection.

Two cases of spontaneous left main coronary artery dissection are reported. This condition is rare and may present as an urgent surgical dilemma. The presentation, diagnosis, and management of primary left main coronary artery dissection are reviewed. Causative factors and underlying pathology are clarified. Prompt diagnosis and surgical intervention with temporary ventricular support is safe and effective.

Two-dimensional diffusion of amphiphiles in phospholipid monolayers at the air-water interface.

Steady-state and time-resolved fluorescence spectroscopy has been used to examine lateral diffusion in dipalmitoyl-L-alpha-phosphatidylcholine (DPPC) and dimyristoyl-L-alpha-phosphatidylcholine (DMPC) monolayers at the air-water interface, by studying the fluorescence quenching of a pyrene-labeled phospholipid (pyrene-DPPE) by two amphiphilic quenchers. Steady-state fluorescence measurements revealed pyrene-DPPE to be homogeneously distributed in the DMPC lipid matrix for all measured surface pressures and only in the liquid-expanded (LE) phase of the DPPC monolayer. Time-resolved fluorescence decays for pyrene-DPPE in DMPC and DPPC (LE phase) in the absence of quencher were best described by a single-exponential function, also suggesting a homogeneous distribution of pyrene-DPPE within the monolayer films. Addition of quencher to the monolayer film produced nonexponential decay behavior, which is adequately described by the continuum theory of diffusion-controlled quenching in a two-dimensional environment. Steady-state fluorescence measurements yielded lateral diffusion coefficients significantly larger than those obtained from time-resolved data. The difference in these values was ascribed to the influence of static quenching in the case of the steady-state measurements. The lateral diffusion coefficients obtained in the DMPC monolayers were found to decrease with increasing surface pressure, reflecting a decrease in monolayer fluidity with compression.

Applying mail response enhancement techniques to health care surveys: a cost-benefit approach.

A study of over 1200 persons gave insights into the effectiveness of different appeals in a mail survey for a health-care facility. The influences of financial incentives, contributions to charity and time appeals were studied. Not only was the practical effectiveness of the three different appeals investigated, the cost of obtaining the response rates with each was also shown. The range of response rates was from 25% to 67%. The average cost per return for the different methods ranged from $2.87 to $5.64. A method of testing for the potential bias in a survey is also presented.

Nonexponential fluorescence decay of aqueous tryptophan and two related peptides by picosecond spectroscopy.

Time-resolved fluorescence spectroscopy of tryptophan and two related dipeptides, tryptophylalanine and alanyltryptophan, has been carried out on the subnanosecond time scale by using picosecond exciting pulses at a wavelength of 264 nm. Detection was with an ultrafast streak camera coupled to an optical multichannel analyzer. The zwitterions of these molecules show a definite nonexponential fluorescence decay which can be analyzed in terms of two exponentials. The two decay rates increase strongly with increasing temperature, as does the weight of the faster component. In tryptophan at pH 11, where the amino group is deprotonated, there remains only a single temperature-dependent exponential. The results are interpreted in terms of two kinds of trapped conformers in the excited state that interconvert no quicker than the time scale of the fluorescence. A model is suggested in which the nonradiative processes in one conformer approximate those in the bare indole moiety. The nonradiative decay rate of the other conformer is substantially faster. It is believed that the process responsible for this fast decay is intramolecular electron transfer from the indole to the amino acid side chain. The predilection for this electron transfer depends on steric relationships as well as on the electron-attracting power of the carbonyl group. This picture is consistent with earlier fluorescence quantum yield results. In fact, a self-consistent picture emerges from the temporal and yield data that quantitatively explains most important facets of tryptophan photochemistry in aqueous solution.