Quantification of pulmonary capillary endothelium-bound angiotensin converting enzyme inhibition in man.

Angiotensin converting enzyme (ACE, kininase II) is an endothelial luminal ectoenzyme expressed abundantly on the pulmonary capillary endothelium and recognized as the site for the conversion of circulating angiotensin I to II. In the present study, we have applied recently developed methodologies for assaying pulmonary capillary endothelium-bound (PCEB) ACE activity in man, to estimate the interaction of an ACE inhibitor (enalaprilat) with PCEB ACE in human subjects. Trace amounts of the specific ACE substrate, 3H-benzoyl-Phe-Ala-Pro (3H-BPAP; 40 Ci or 2 nmol), was injected as a bolus into the subclavian vein and immediately blood was withdrawn from a radial arterial catheter. Plasma concentrations of surviving substrate and product (3H-benzoyl-Phe) were estimated and BPAP utilization was calculated during a single transpulmonary passage, at baseline (T(0)) and at 15 min (T(15)) and 2 h (T(120)) after intravenous administration of 1.5 g/kg enalaprilat in 12 normotensive subjects. This treatment had no significant effect on mean arterial pressure (91+/- 6 vs. 84 +/- 7 vs. 88 +/- 6 mm Hg for T(0), T(15) and T(120), respectively), but significantly decreased serum and PCEB ACE activities. When normalized to predrug (T(0)) activity levels, enalaprilat inhibited PCEB and serum ACE activities at T(15) 74 +/- 6% and 68 +/- 6%, respectively. However, 2 h after enalaprilat (T(120)), PCEB ACE inhibition was maintained at 66 +/- 7%, whereas serum ACE inhibition was reduced to 46 +/- 8% (P<.01 from PCEB ACE), suggesting a preferential PCEB ACE inhibitory effect of enalaprilat.

Aortic valve rheumatoid nodules producing clinical aortic regurgitation and a review of the literature.

The majority of cardiac involvement in rheumatoid arthritis (RA) is an incidental finding at postmortem, as less than 3% of patients with RA have clinical cardiac signs or symptoms. Most cardiac involvement in RA involves the pericardium and has been known since Charcot first described an RA patient with pericarditis in 1881. Cardiac involvement takes two different forms: non-specific inflammatory changes and specific granuloma formation. Specific rheumatoid nodules in the heart are an infrequent complication of RA. This is the first case report of a surgically excised heart valve with rheumatoid nodules. A 74-year-old RA patient with a high seropositive rheumatoid factor presented with severe aortic regurgitation and underwent a valve replacement. The native aortic valve showed significant stenosis with multiple, classic rheumatoid nodules.

cGMP accumulation and gene expression of soluble guanylate cyclase in human vascular tissue.

Gene expression of soluble guanylate cyclase (sGC) and cGMP accumulation in response to sodium nitroprusside (SNP) were studied in cultured human vascular cells and freshly harvested vascular tissue. As revealed by reverse transcriptase-polymerase chain reaction, cultured smooth muscle and endothelial cells, as well as freshly isolated human vascular tissue, express mRNA for the alpha 3 and beta 3 subunits but not for the alpha 2 and beta 3 subunits is evident even in the absence of increased cGMP accumulation in response to SNP. cGMP accumulation in human cells cultured from different vascular beds typically increased two- to five-fold (maximum of 11.4-fold) over baseline following stimulation with 100 microM SNP. Bovine, murine, canine, and avian vascular smooth muscle cells accumulated similar or lower amounts of cGMP than human cells, whereas porcine, rat, and rabbit smooth muscle cells accumulated greater amounts of cGMP. In freshly harvested human vessels, cGMP accumulation in response to SNP was found to increase fifteen-fold over baseline. In contrast to the SNP-induced cGMP accumulation, cGMP levels in response to particulate guanylate cyclase activator atriopeptin II were equal to or greater in cultured human cells than in fresh human vascular tissue. We conclude that human vascular cells (fresh and cultured) express the mRNA for both a large (alpha 3) and a small (beta 3) sGC subunit and that fresh human cells are more sensitive to SNP stimulation.

The use of methylene blue as an extravascular surgical marker impairs vascular responses of human saphenous veins.

Methylene blue is occasionally applied to the adventitia of blood vessels during coronary artery bypass and other vascular procedures to assist in the orientation of the vessel. Inherent in this method is the assumption that extravascular application of methylene blue is innocuous with regard to vascular function. In the first part of this study, the in vitro vascular reactivity of methylene blue-labeled saphenous veins was compared with that of veins that were not marked with methylene blue. The vasoactive agents tested were designed to examine multiple pathways. They included potassium chloride, prostaglandin F2 alpha, phenylephrine, serotonin, angiotensin II, BHT-933 (alpha 2-adrenergic agonist), sodium nitroprusside, acetylcholine, isoproterenol, and verapamil. Compared with unmarked veins, those marked with methylene blue demonstrated a significant impairment of both vasoconstrictor and vasodilator function. These observations were made on a relatively small number of patients and could therefore be attributed to inherent differences between patients or surgical procedures. In the second part of this study, these variables were eliminated by dividing a single vein from one patient into three segments for a 45-minute exposure to external only methylene blue, internal and external methylene blue, or no methylene blue. The segments were then evaluated for vasoreactivity in vitro. Externally applied methylene blue reduced vasoconstriction regardless of the agonist. Further, both endothelium-dependent and -independent vasodilation was diminished by external methylene blue exposure. In veins exposed to methylene blue both internally and externally the results were similar but the magnitude of impairment greater. It is concluded that surgical marking of blood vessels with methylene blue has the potential to adversely affect vascular reactivity and therefore the use of alternative dyes should be considered.

Intrathoracic biopsies, pulmonary wedge excision, and management of pleural disease: is video-assisted closed chest surgery the approach of choice?

Few studies define differences between video-assisted thoracic surgery (VATS) over conventional posterolateral thoracotomy (PLT) for limited procedures. We propose that length of hospital stay (LOS), the days of requirement for narcotic analgesia (DNA) by epidural, intravenous, intramuscular, or oral administration, operating time (OT), return to pre-operative functional status (RT), and the achievement of a therapeutic objective are not dependent on the approach taken (VATS or PLT) for selected diagnostic and therapeutic procedures for pleural, pulmonary, or mediastinal disease. A total of 102 consecutive patients (52 males, 50 females, age 48 +/- 16 years) were eligible to undergo (VATS) for diagnosis and/or treatment of lung lesions, pleural disease, persistent pneumothorax or mediastinal lesions. Seventy-two underwent VATS only and 21, conventional posterolateral thoracotomy (PLT). Nine VATS patients were converted to PLT, for completion of lobectomies after VATS staging of resectable malignancy (6), extensive decortication (2), and giant bullectomy (1). VATS and PLT were compared according to OT, LOS, DNA, RT, achievement of diagnostic and/or therapeutic objective, and morbidity and mortality. After VATS only and PLT only, LOS was 4.8 +/- 2.7 and 7.8 +/- 4.6 days, respectively (P < .03). DNA was 3.4 +/- 2.1 and 6.1 +/- 3.6 days after surgery, respectively (P < .01). RT was 12.0 +/- 11.2 and 21.4 +/- 9.5 days, respectively (P < .01). OT was 80 +/- 34 and 95 +/- 32 minutes, respectively (P = ns). Among 9 conversions from VATS to PLT LOS was 11.4 +/- 5.5, DNA 6.9 +/- 4.4 and RT 20.1 +/- 6.0 days.(ABSTRACT TRUNCATED AT 250 WORDS)

Crohn's disease of the esophagus.

We report a case of Crohn's esophagitis involving the entire intrathoracic esophagus, and without evidence of inflammatory bowel disease elsewhere, that was treated successfully with esophagectomy. The clinicopathologic features and the literature are reviewed.

Video-assisted thoracic surgery: the approach of choice for selected diagnosis and therapy.

Unconvinced of the benefits of video-assisted thoracic surgery (VATS) over conventional posterolateral thoracotomy (PLT) we undertook an evaluation of the VATS approach for various diagnostic and therapeutic intrathoracic procedures. For the 18 months ending December 31, 1992, 55 consecutive patients (28 males, 27 females, age 48 +/- 17 years) were eligible to undergo VATS for diagnosis and/or treatment of a variety of conditions. Thirty-eight were chosen for VATS and 17 for PLT. Three VATS patients were converted to PLT (7.9%). Thus 35 VATS patients formed our first experience with the minimally invasive approach. We observed operating time (OT), length of stay (LOS), days of postoperative narcotic use (DNA), achievement of diagnostic and/or therapeutic objectives and morbidity and mortality. For analysis of LOS and DNA due to the procedure alone patients were outliers if LOS was prolonged for reasons other than the procedure, pain or related complications. For estimation of anticipated LOS and DNA due to VATS, 9 of the 35 VATS patients were outliers. For the remaining 26, LOS was 4.9 +/- 2.5 days and DNA was 2.6 +/- 1.7 days after surgery. For the 35 VATS patients OT was 87 +/- 30 minutes. Complications after VATS were few and similar to those experienced after PLT. A diagnostic and/or therapeutic objective was achieved in all patients without mortality. We found that definitive procedures carried out with VATS require fewer hospital days and less postoperative analgesia than expected after similar procedures performed through standard PLT. Diagnostic and therapeutic objectives are easily attainable and complications are few. (ABSTRACT TRUNCATED AT 250 WORDS)

Reduction of peak inspiratory pressure using high frequency jet ventilation and pressure control ventilation following pneumonectomy.

High peak inspiratory pressure (PIP) during mechanical ventilation is associated with increased risk of barotrauma. High frequency jet ventilation (HFJV) and pressure control ventilation (PCV) have been advocated for the reduction of PIP. The Food and Drug Administration has approved HFJV, respiratory frequency as high as 150 breaths per minute (bpm); however, bpm greater than 150 are still considered for experimental use. At less than 40 bpm, the point where HFJV is no longer considered to be high frequency, PCV is substituted which then becomes the mode of choice because of the ability to control ventilating pressures by setting the PIP. We present a case in which we used these two forms of ventilation for reducing the risk of stump blowout and barotrauma following pneumonectomy.

Echocardiographic detection of an infected superior vena caval thrombus presenting as a right atrial mass.

A patient was found to have a large mobile right atrial mass by two-dimensional echocardiography after developing sepsis due to prolonged central hyperalimentation. Contrast echocardiography was helpful in localizing the origin of the mass. A large infected thrombus emanating from the superior vena cava was removed at operation. The discussion includes a review of the literature on the echocardiography of right atrial masses.

Right atrial thrombus formation following central venous dialysis catheter placement.

Silicone rubber central venous dialysis catheters are used to provide vascular access in acute renal failure patients and in chronic dialysis patients in whom conventional vascular access cannot be achieved or maintained. The use of these catheters is not without hazard. The first reported case of right atrial thrombus formation associated with the use of a double lumen silicone rubber central hemodialysis catheter is described. This patient's course points out another potential complication of this type of vascular access and emphasizes the importance of removing such catheters in a timely fashion when they are no longer required for dialysis.

Repair of aneurysms of the thoracic aorta: 12-year experience in a high-risk population.

We present our 12-year experience with surgical treatment of aneurysms of the thoracic aorta in a high-risk patient population. Of 52 patients with aneurysms, 36 patients, aged 19 to 80 years, had operation. In 24 of the 36, there were three or more associated major disease processes, such as chronic bronchitis, hypertensive cardiovascular disease, aortic valve disease, cerebrovascular disease, abdominal aortic aneurysm, and coronary artery disease. Eight patients with acute type A (ascending aorta) and seven with acute type B (descending aorta) aneurysms had emergency repair, with survival in four and seven, respectively. All patients with chronic type A or B aneurysms had elective repair, and all patients with acute or chronic type A aneurysms had surgical treatment. Four patients with acute type A and two with acute type B aneurysms had elective operation, with survival in three and one, respectively. Nine patients with chronic type A and six with chronic type B aneurysms had elective operation, and all survived. Twelve patients with chronic type B aneurysms did not have operation, and all were alive at early follow-up. Mortality for patients having acute type A aneurysms requiring emergency operation was greater than that after elective repair of acute or chronic type A aneurysms. Short-term survival for chronic type B aneurysms was similar whether the patient was treated medically or surgically.

Congenital absence of pericardium: an unusual cause of atypical angina.

Congenital defects of the pericardium are unusual. Patients may experience exertional chest pain, cardiac arrhythmias, syncope, sudden death, or incarceration of myocardium, or they may be entirely asymptomatic. We describe the case of a symptomatic pericardial herniation diagnosed by echocardiography and confirmed by cineangiography. Successful repair was accomplished using a polytetrafluoroethylene soft-tissue prosthesis.

Disc immobilization of Björk-Shiley and Medtronic Hall valves during and immediately after valve replacement.

During the last fourteen years, 377 unileaflet tilting-disc prosthetic valves (Björk-Shiley and Medtronic Hall) have been used for single or multiple valve replacements with and without concomitant coronary artery by-pass grafting. In the past five years, five instances of disc immobilization (three in the mitral and two in the aortic position) occurred either at the time of weaning from cardiopulmonary bypass or immediately thereafter. When the implanted site of the prosthetic valve was the mitral position, reexploration in 2 patients revealed chordal remnants in the subannular area stuck between the disc occluder and the valve ring, thereby immobilizing the disc. In the third instance, the free movement of the disc was impeded by the left ventricular myocardium. In the aortic position, an unraveled suture impacted between the disc occluder and the valve ring immobilized the disc in 1 patient. In the other patient, the cause of the malfunction could not be determined at the time of reexploration. The 1 death among these 5 patients was directly related to the malfunction of the prosthesis. The mechanism, recognition, treatment, and prevention of this catastrophic malfunction of tilting-disc valves are discussed.

Esophageal mucocele: a complication of blind loop esophagus.

Mucocele of the bypassed esophagus is an unusual complication of esophageal replacement and has been described only in isolated references. This report is based on our experience with 6 patients in whom a mucocele developed following esophageal replacement. Esophageal replacement was performed on 37 patients over a 10-year period at the Medical College of Georgia Hospital. A symptomatic mucocele requiring excision developed in 3 patients with achalasia, 1 with congenital tracheoesophageal fistula, 1 with esophageal atresia, and 1 with inflammatory stricture. Conduits used included stomach (4), reversed gastric tube (1), and colon (1). Our experience indicates that conversion of a closed-loop esophagus into a symptomatic mucocele is more likely in the presence of functioning, chronically irritated mucosa. The clinical features were referable to the mucocele itself or respiratory embarrassment therefrom. Thoracic roentgenograms and computed tomographic scans were diagnostic in verifying the presence of the esophageal mucocele. All five mucoceles arose from squamous epithelium. One of 3 patients with achalasia in whom a mucocele developed following esophageal replacement had premalignant changes in the mucosa. Based on this experience, our treatment of choice is early, complete excision of the mucocele.

Two decades of experience with modified Heller's myotomy for achalasia.

We reviewed the hospital records of 36 patients who underwent modified Heller's myotomy for achalasia between January, 1961, and December, 1982. There were 18 male and 18 female patients ranging between 17 months and 75 years old. The most frequent symptom was dysphagia, followed by regurgitation of ingested food and weight loss. Modified Heller's myotomy was performed through a transthoracic incision in 35 patients and a transabdominal incision in 1. An antireflux procedure in addition to esophagomyotomy was performed in 20 patients. There was 1 postoperative death. Thirty-three patients were followed up for periods ranging from 9 months to 21 years. The results were considered good in 27, fair in 2, and poor in 4. One of the 4 underwent repeat esophagomyotomy 71/2 years after the initial operation with a good result. The remaining 3 had an antireflux procedure at the time of esophagomyotomy. Because of recurrence of symptoms, esophagogastrostomy was performed in 1 and colon interposition in 2. These results suggest that an antireflux procedure should not be added to modified Heller's operation in the treatment of achalasia.

Thoracic duct injury from blunt trauma.

We have reported a case of traumatic chylothorax occurring as a rare complication of fracture dislocation of the dorsal spine. When conservative management by drainage, low-fat diet, and parenteral alimentation proved unsuccessful, thoracic duct ligation effected a cure.

Current physiologic pacemakers: a serious problem with a new device.

Twenty adults underwent implantation of an automatic (DDD) pacemaker (Medtronic model 7000, Versatrax I) for treatment of symptomatic bradyarrhythmias. Only 9 patients had optimal DDD mode pacing during 78 paced months. In 3 patients, the DDD mode was changed to atrioventricular (AV) sequential (DVI) early because of risk imposed by sustained tachycardia upon underlying myocardial ischemia. The remaining 8 had had tachycardia due to pacemaker reentry, and 7 had neurologic and cardiovascular symptoms. DDD pacing was abandoned in 5 when reentry could not be interrupted by digitalis administration or reprogramming. Three continue to be paced in DDD mode despite intermittent reentrant tachycardias, with digitalis diminishing episodes of reentry in only 1. Mean ventriculoatrial conduction time was 229 +/- 34 ms. Reentrant pacemaker tachycardia developed in 7 of 12 with normal or nearly normal AV conduction, but in only 1 of 5 with complete heart block. Preimplantation electrophysiologic study did not reliably detect and initial postoperative Holter monitoring did not predict reentrant tachycardia. The risk of reentry caused by a short, fixed atrial refractory period combined with the high occurrence of slow retrograde AV conduction, particularly in patients with normal or nearly normal anterograde conduction, renders the Versatrax I and other similar pacemakers unsuitable for DDD mode pacing in many patients.