Calcification of aortic versus mitral porcine bioprosthetic heart valves: a radiographic study comparing amounts of calcific deposits in valves explanted from the same patient

Calcium detected by radiography was compared in 10 pairs of aortic and mitral glutaraldehyde-treated porcine bioprosthetic heart valves explanted from 10 patients (7 men and 3 women), aged 19 to 68 years (mean 43). Both valves of 6 pairs of valves had undergone primary tissue failure (revealed by cardiac catheterization and angiography) and 1 valve of the other 4 pairs of valves had undergone primary tissue failure. These porcine valves had been implanted from 2 1/4 to 9 years (mean 5 3/4). All 20 explanted valves contained calcium. The grade of calcium was the same in 4 pairs of valves (grade 2+ or 3+), and 1 grade different in 4 pairs of valves (grade 1+ to 4+), with the greater calcium evenly divided between the 2 valve positions. There was more than 1 grade greater mitral valve calcium in 2 pairs of valves (grade 3+ and 4+ mitral vs 1+ and 2+ aortic, respectively). Thus, calcium is usually present in both aortic and mitral valve positions when bioprosthetic valves of this type in either valve position fail as a result of primary tissue failure, and radiographic calcium in porcine bioprosthetic valves is usually similar in grade in both the aortic and mitral valve positions.

Independent determinants of operative mortality for patients with aortic dissections

A 20 year (1963 to 1982) surgical experience including 175 consecutive patients with aortic dissections was analyzed by logistic discriminant analyses to identify predictors of high operative risk. The patient population had characteristics similar to those in large autopsy series. Sixty-nine percent had type A and 58% had acute dissections. The intimal tear was located in the ascending aorta in 60% of the patients, the descending aorta in 27%, and the transverse arch in 13%. The overall operative mortality rate was 23 +/- 3%. The operative mortality rates were substantially lower between 1977 and 1982: mortality in patients with acute type A dissections, 7 +/- 5%; in those with chronic type A, 11 +/- 7%; in those with acute type B, 13 +/- 12%; and in those with chronic type B, 11 +/- 11%. After preliminary univariate screening, the following factors were determined to be significant independent predictors of operative mortality (in rank order of declining predictive power): type A patients (n = 121), renal dysfunction, tamponade, renal/visceral ischemia, and operative date; type B patients (n = 54), rupture, renal/visceral ischemia, and age; all patients (n = 175), renal dysfunction, renal/visceral ischemia, site of tear (ascending less than descending less than arch), tamponade, operative date, and pulmonary disease. Interestingly, several variables had no important bearing on operative mortality, including type (acute vs chronic) of dissection, age, previous operation, rupture, stroke, paraplegia, Marfan's syndrome, concomitant aortic valve replacement and/or coronary artery bypass grafting, site of tear, and whether or not the tear was resected in type A patients; emergency operation, hypertension, previous cardiac symptoms, paraplegia, site of tear, and resection of tear in type B patients; and, when all patients were considered together, age, sex, cardiac symptoms, prior operation, stroke, paraplegia, acute myocardial infarction, acute aortic regurgitation, Marfan's syndrome, and tear resection. These data allow calculation of any individual patient's operative risk and document that the operative mortality rate today is relatively low for all patients with aortic dissections, irrespective of type or acuity. Earlier surgical referral of patients with acute type A or acute type B dissection before irreversible major end-organ ischemia and/or infarction is probably in part responsible for the substantially improved results since 1977.

Severe superior vena cava syndrome and hydrocephalus after the Mustard procedure: findings and a new surgical approach

Some degree of obstruction of the superior vena cava is common after the Mustard operation for transposition of the great arteries. This can cause superior vena cava syndrome, which in extreme cases may lead to hydrocephalus in young children. While revision of the intra-atrial baffle can be performed, this procedure is associated with significant morbidity and mortality and may not resolve the problem. We describe an alternative operative approach in a group of patients who had superior vena cava syndrome after the Mustard procedure: anastomosis of the innominate vein to the left atrial appendage. This procedure is not complicated to perform and is safe; symptoms were relieved in all patients.

Mechanoreceptors in human cruciate ligaments. A histological study

We obtained human cruciate ligaments at the time of total knee replacement and from autopsy and amputation specimens, and examined histological sections of the ligaments for the presence of mechanoreceptors using the Bodian, Bielschowsky, and Ranvier gold-chloride stains for axons and nerve-endings. The cruciate ligaments obtained at the time of total knee replacement were too distorted by disease processes to be of use. The autopsy and amputation specimens, however, contained fusiform mechanoreceptor structures measuring 200 by seventy-five micrometers, with a single axon exiting from the capsule of the receptor. One to three receptors were found at the surface of each ligament beneath the synovial membrane, and were absent from the joint capsules and menisci. Morphologically the receptors resembled Golgi tendon organs, and it seems likely that they provide proprioceptive information and contribute to reflexes inhibiting injurious movements of the knee. This is the first histological demonstration of mechanoreceptors in human cruciate ligaments.

Dobutamine and dopamine after cardiac surgery: greater augmentation of myocardial blood flow with dobutamine

Left ventricular hemodynamics, dimensions and coronary sinus blood flows were measured simultaneously after infusions of dobutamine and dopamine. Ten patients were studied 6, 10 to 15, and 24 hr after cardiopulmonary bypass surgery. The dose of each drug was adjusted to increase cardiac output by 25%. Heart rate was held constant with atrial pacing. Dobutamine and dopamine increased peak left ventricular dP/dt from baseline values by 72% vs 58% during the early study, 77% vs 78% in the intermediate study, and 95% vs 79% in the late study (all NS, difference between drugs). Similarly, there were no significant differences in hemodynamic response or in cardiac dimensions after the two drugs in any period. Both drugs increased myocardial oxygen uptake during the intermediate and late studies (32% vs 33% and 34% vs 25%). With dobutamine this increase was matched by a similar increase in coronary blood flow; however, failure of the expected increase in coronary blood flow with dopamine suggested coronary constriction. Although dobutamine and dopamine have similar hemodynamic effects, dobutamine has the advantage of not limiting the increase in coronary blood flow associated with increased oxygen demand.

Performance characteristics of the Starr-Edwards Model 1260 aortic valve prosthesis beyond ten years

The Starr-Edwards non-cloth-covered silicone ball (Model 1260) aortic valve prosthesis has been widely used for over 15 years and remains a standard against which newer values are compared. To define more completely the performance characteristics of this prosthesis, this study (including 449 patients) analyzed the long-term function of this specific valve over a cumulative total of 2,896 patient-years (pt-yrs) of follow-up which extended beyond 13 years. Expressed in both actuarial (% [+/- standard error of the mean] free at 10 years) and linearized (%/pt-yr) terms, respectively, valve-related complications occurred at the following rates: thromboembolism, 76 +/- 3 and 2.7; anticoagulant-related hemorrhage, 74 +/- 3 and 3.1; prosthetic valve endocarditis, 92 +/- 2 and 0.9; reoperation, 90 +/- 2 and 1.1; valve failure, 82 +/- 2 and 2.2; all valve-related morbidity and mortality, 51 +/- 3 and 6.0; and valve-related death, 88 +/- 2 and 1.3. Thirteen percent of hospital and 18% of late deaths were due to valve-related causes. No case of structural failure was documented. This prosthesis has an admirable structural durability record out to 13 years, and its long-term performance is satisfactory, albeit not optimal. Despite the indestructable design and construction of this mechanical valve substitute, 12% +/- 2% of patients had died of valve-related complications by 10 years, and fully 49% +/- 3% had had some form of serious valve-related complication. The long-term data reported herein can be used for analytical comparison when follow-up of patients with newer mechanical prostheses and tissue bioprostheses reaches 10 years to elucidate whether or not these newer valves truly represent improvements and which type of valve substitute proffers the most possible net benefit to the patient.

Surgical implications of low cardiac output syndrome after myocardial infarction

There is a spectrum of conditions that can occur after severe myocardial infarction which cause inadequate cardiac output. Severe and generalized infarction may result in inadequate perfusion of sufficient myocardium to maintain the cardiac work load. Management is limited to supportive measures, including the use of the intraaortic balloon pump. More localized defects of myocardial blood supply can give rise to myocardial rupture. These ruptures may occur in the free wall, within the septum, or within a papillary muscle. Conservative therapy is only indicated as long as improvement continues. Surgical measures should not be delayed in the face of clinical deterioration. They consist of debridement of dead tissue and repair of the defect (or mitral valve replacement if papillary muscle rupture is present).

Aneurysmal degeneration of Blalock-Taussig shunts: identification and surgical treatment options

Many Blalock-Taussig shunts (subclavian to pulmonary artery anastomoses) have been created and a significant number are still being done. Two cases of aneurysmal degeneration of a Blalock-Taussig shunt and their management are described. Development of this rare complication may be related to large shunt flow and long duration. Large, symptomatic or enlarging aneurysms should be repaired and smaller ones studied by serial computed axial tomography. A simple and safe approach to correct this lesion is division and oversewing of the proximal subclavian artery through an anterior approach, assuming adequate pulmonary blood flow is already present or can be established concomitantly.

Prosthetic valve endocarditis caused by Legionella pneumophila

Prosthetic valve endocarditis due to Legionella pneumophila occurred in a woman who had aortic and mitral valve replacements with porcine xenografts. During surgery for persistent fever and aortic regurgitation due to presumed endocarditis, she had vegetations involving both the aortic and mitral valve prostheses with a circumferential abscess of the aortic annulus. Cultures, Dieterle stain, and direct fluorescent antibody stain of valve tissue, and subsequent measurements of serum antibody levels confirmed L. pneumophila as the infecting organism. This infection occurred in the absence of pneumonia. Legionella pneumophila must be considered a potential cause of culture-negative prosthetic valve endocarditis and should be sought in appropriate clinical circumstances.

Nature of the renal injury following total renal ischemia in man

The effects of total renal ischemia (TRI) of 15-87 min duration due to suprarenal clamping of the aorta were studied in 15 mannitol-treated patients undergoing abdominal aortic surgery. 15 patients undergoing similar surgery but requiring only infrarenal clamping served as controls. 1-2 h following TRI, GFR was reduced to only 39% of that in controls, 23 +/- 5 vs. 59 +/- 7 ml/min (P less than 0.001). This could not be ascribed to impaired renal plasma flow (RPF), which was mildly reduced to 331 +/- 71 and was not different from the value in controls, 407 +/- 66 ml/min. However, impaired PAH extraction (43 +/- 7%) and isosthenuria, not present in controls, suggest a primary role for tubular injury in lowering GFR at this time. 24 h following TRI, the GFR remained depressed below controls, 45 +/- 8 vs. 84 +/- 8 ml/min (P less than 0.005), while the transglomerular sieving of neutral dextrans was significantly enhanced (radius interval, 24-40 A). A theoretical analysis of transcapillary solute exchange revealed that these findings could be largely explained by a selective reduction of either RPF (-61%) or of transmembrane hydraulic pressure difference (-18%) below control values. Alternately, a combination of these two factors with changes of smaller magnitude could explain the findings. In contrast, a selective increase in oncotic pressure or decrease of the glomerular ultrafiltration coefficient could be excluded as a cause of hypofiltration 24 h after TRI. These observations lead us to suggest that the transient azotemia observed following TRI is due to a self-limited injury to the nephron that is identical to that seen in overt and sustained forms of acute renal failure.

Aneurysm of the diverticulum of the ductus arteriosus in the adult. Successful surgical treatment in five patients and review of the literature

Sixteen aneurysms of the diverticulum of the ductus arteriosus in adults have been previously reported. Ten patients died of rupture of the aneurysm or died at surgical exploration. Only one previous patient underwent successful aneurysmectomy. Five new cases of aneurysm of the adult ductal diverticulum, all diagnosed preoperatively and successfully repaired, are presented. All five patients are alive 6 to 33 months postoperatively. Our experience with these patients suggests several important features of these aneurysms: (1) Diagnosis may be difficult and may require multiple-view aortography or computed tomographic (CT) scanning to differentiate from tumor. (2) The operative approach, either left thoracotomy or median sternotomy, may be determined by the necessity for concomitant procedures. (3) Unlike true atherosclerotic aneurysms of the aortic arch, these aneurysms can be repaired effectively by aneurysmorrhaphy. (4) Because of their critical location and the high incidence of complications in reported cases, aneurysms greater than 3 cm in diameter, those producing symptoms, or those showing progressive enlargement should be surgically resected.

Digital subtraction angiography of aortic dissection

Digital subtraction angiography (DSA) was used to study six patients with aortic dissection, five of whom had undergone surgical repair. One patient had both pre- and postoperative evaluations. DSA with intravenous contrast administration is a relatively noninvasive procedure that provides diagnostic images in projection format allowing assessment of the extent of aortic dissection and involvement of important aortic branches. Postacquisition reprocessing techniques unique to DSA optimize the imaging information regarding flow dynamics of the true and false channels.

Villous adenoma of the urinary bladder: a morphologic or biologic entity?

Villous adenomas in the urinary bladder are rare neoplasms whose malignant potential is unclear. A case of a morphologically benign non-invasive mucin producing papillary neoplasm of the urinary bladder associated with cystitis glandularis is presented. Absence of A tissue isoantigen from the neoplastic and metaplastic cells and the presence of H tissue isoantigen in both neoplastic and metaplastic cells is observed in a patient whose blood type is A, indicating incomplete maturation of surface coat constituents. The histologically benign appearance of this lesion may belie a malignant potential.

Veno-venous allografts: patency, subendothelial proliferation, and the role of platelet-active agents

Patency and histology of 81 vein allografts and 10 autografts in the canine femoral venous system were compared and the effect of platelet active agents in altering patency rates and subendothelial proliferation in allografts was examined. It was found that allografts thrombose at a predictable interval after operation (18 +/- 7 days) and have significantly worse survival than autografts (P less than 0.001). Platelet-active agents did not alter allograft patency rate of the incidence of subendothelial proliferation in this model.

Discriminant analysis of the changing risks of coronary artery operations: 1971-1979

The risk of perioperative myocardial infarction (PMI) and operative mortality (OM) associated with coronary artery bypass grafting (CABG) has declined since the introduction of this procedure 15 years ago. Rigorous scientific investigation of the reasons for this trend has been hindered by the complex interactions between changing indications for operation, criteria for patient selection, and management methods. Using univariate and multivariate logistic regression analyses, we investigated the effects of 42 variables on PMI and OM for two cohorts undergoing CABG between 1971 and 1975 (Group A) and 1977 and 1979 (Group B). According to previously identified risk factors, Group B patients were at higher potential risk than those in Group A. Nevertheless, the PMI and OM rates declined from 8.7% +/- 0.9% to 4.6% +/- 0.7% (p = 0.005) and from 2.4% +/- 0.5% to 1.2% +/- 0.4% (p = 0.07), respectively. In calendar year 1979 (N = 438), the PMI and OM rates were 2.8% +/- 0.8% and 0.7% +/- 0.4%. More importantly, the independent determinants of PMI and OM for the two time intervals were distinctly different. Factors which affected the PMI rate in Group A were no longer determinants of PMI in Group B; with the exception of emergency operation and, to a modest extent, congestive heart failure (CHF), predictors of OM in Group A were not determinants of OM in Group B. Thus the adverse impact of multiple patient-related and disease-related determinants of PMI and OM has been neutralized over this decade by the real improvements in patient management. The specific factors and management concepts responsible for these superior results in sicker patients remain uncharacterized; however, in general terms, more sophisticated medical, anesthetic, and nursing management and more refined surgical expertise have essentially nullified the concept of high-risk candidates. Furthermore, the more propitious early results being attained currently may translate directly into parallel long-term improvements in functional benefit and survival.

Proliferative variability of endothelial clones derived from adult bovine aorta: influence of fibroblast growth factor and smooth muscle cell extracellular matrix

Four endothelial cell clones derived from adult bovine aorta were examined with respect to their proliferative characteristics in vitro. Three of these clones, derived in the absence of fibroblast growth factor (FGF), displayed variable basal proliferative rates. One of these non-FGF derived clones grew at a maximal rate which could not be further enhanced with FGF. The other two clones grew at a suboptimal rate which was stimulated by low doses of FGF (10-50 ng/ml) and inhibited by higher doses (100-250 ng/ml). The fourth clone, derived in the presence of FGF, was stimulated by FGF in a dose-dependent manner (10-250 ng/ml) and was not growth inhibited at high FGF concentrations (250-1,000 ng/ml). Growth of all four clones on extracellular matrix (ECM) derived from bovine aortic smooth muscle (BASM) cells was optimal in the absence of FGF. ECM-coated dishes also significantly increased the sensitivity of all clones by at least fivefold to mitogenic stimulation by serum. The proliferative lifespans of the clones ranged between 60 and 120 generations with the most actively proliferating clones attaining the greatest lifespan. Continuous subculture of two of the endothelial clones in the presence of FGF or on ECM-coated dishes did not induce a dependence of the cells on either factor for subsequent growth in its absence. The results indicate that aortic endothelial cells display considerable clonal variability in ther basal proliferative rate and in their response to FGF. This clonal variability is not observed when the cells are maintained on ECM-coated dishes derived from vascular smooth muscle cells.

Two-dimensional echocardiographic analysis of segmental left ventricular wall motion before and after coronary artery bypass surgery

Twenty patients with coronary artery disease were studied with two-dimensional echocardiography the day before saphenous vein bypass graft surgery. Serial studies were obtained 7.4 +/- 2.5 (+/- SD) and 43.4 +/- 13.1 days postoperatively to qualitatively assess the effect of bypass surgery on regional wall motion. Changes in segmental wall motion were assessed semiquantitatively by assigning a segmental wall motion score to each of nine echocardiographically defined segments. Preoperatively, 18% of the segments moved abnormally. The mean overall segmental wall motion score did not change significantly, as shown by comparing the postoperative studies with the preoperative study. However, there was a significant worsening in the septal motion (apical and basal) and a significant improvement in posterior wall motion (apical and basal) after bypass surgery. Anterior and lateral wall motion were not significantly changed. Nonseptal segments that were normal preoperatively usually remained normal; abnormal nonseptal segments usually improved or were unchanged by surgery. The motion of septal segments, however, generally worsened postoperatively whether they were normal or abnormal preoperatively. We conclude that segmental wall motion assessed by two-dimensional echocardiography may improve after revascularization surgery, but the interventricular septum shows impaired motion. This effect of coronary artery bypass on wall motion is better demonstrated relatively late after operation than early in the postoperative course, as has been done in some previous studies.