Donor availability as the primary determinant of the future of heart transplantation

Heart transplantation has now achieved a therapeutic status similar to that of cadaveric renal transplantation. Depending on patient selection criteria, it is estimated that as many as 15,000 people per year could conceivably benefit from a heart transplant, but the actual number of persons who will benefit is severely constrained by donor supply. Availability of heart donors was estimated based on data obtained on 1,955 organ donors in the United States. The results show that because of age and other contraindications, only 400 to 1,100 viable donor hearts may be available each year. Donor supply is the most critical determinant of the future of heart transplantation since it will dictate the number of transplants performed, the survival of transplant recipients, the total program expenditures associated with heart transplantation, the nature of the legal and ethical issues involved, the number of cardiac transplant programs required to make optimal use of the available donor hearts, and the future role of mechanical circulatory support systems.     

Image processing in digital chest radiography: effect on diagnostic efficacy.

The usefulness of digital image processing of chest radiographs was evaluated in a clinical study. In 54 patients, chest radiographs in the posteroanterior projection were obtained by both 14 inch digital image intensifier equipment and the conventional screen-film technique. The digital radiographs (512 x 512 image format) viewed on a 625 line monitor were processed in three different ways: (1) standard display; (2) digital edge enhancement for the standard display; and (3) inverse intensity display. The radiographs were interpreted independently by three radiologists. The diagnoses were confirmed by CT, follow-up radiographs and clinical records. Chest abnormalities of the films analyzed included 21 primary lung tumors, 44 pulmonary nodules, 16 cases with mediastinal disease and 17 cases with pneumonia/atelectasis. Interstitial lung disease, pleural plaques, and pulmonary emphysema were found in 30, 18 and 19 cases, respectively. The sensitivity of conventional radiography when averaged overall findings was better than that of the digital techniques (P less than 0.001). The differences in diagnostic accuracy measured by sensitivity and specificity between the three digital display modes were small. Standard image display showed better sensitivity for pulmonary nodules (0.74 vs 0.66; P less than 0.05) but poorer specificity for pulmonary emphysema (0.85 vs. 0.93; P less than 0.05) compared with inverse intensity display. We conclude that when using 512 x 512 image format, the routine use of digital edge enhancement and tone reversal at digital chest radiographs is not warranted.     

Electrocardiographic changes during and after isoflurane-induced hypotension for neurovascular surgery

We evaluated the effects of isoflurane anaesthesia and induced hypotension in 33 neurosurgical patients by electrocardiographic monitoring and serial cardiac enzyme measurements. An electrocardiogram (ECG) and serum enzymes were obtained preoperatively, intraoperatively and postoperatively in the recovery room and for three consecutive days. ECG leads II, V1 and V5 were monitored continuously during anaesthesia. Patients who had had a subarachnoid haemorrhage and a high incidence of abnormal preoperative ECG (42 per cent). Ten patients developed ECG changes intraoperatively, but these changes were unrelated to isoflurane-induced hypotension. Fifty-three per cent of patients developed an abnormal postoperative ECG. These abnormalities consisted mostly of nonspecific ST segment or T wave changes. At no time was there an elevation in cardiac enzyme activity. We found that nonspecific ECG changes are relatively common in patients undergoing vascular neurosurgical procedures. There was no enzymatic evidence of myocardial infarction and we can only speculate that these ECG changes are related to intracranial surgical manipulation.     

Endothelium-dependent and -independent effects of exogenous ATP, adenosine, GTP and guanosine on vascular tone and cyclic nucleotide accumulation of rat mesenteric artery.

1. The effects of exogenous guanosine 5'-triphosphate (GTP) and guanosine on vascular tone and cyclic nucleotide accumulation of noradrenaline-precontracted endothelium-intact and endothelium-denuded rat mesenteric artery rings were compared with the effects of the known purinoceptor agonists adenosine 5'-triphosphate (ATP) and adenosine. 2. GTP (10 microM-1 mM) dose-dependently relaxed endothelium-intact mesenteric artery rings by producing a rapid initial response followed by sustained relaxation resembling the relaxant response to acetylcholine. GTP also slightly relaxed endothelium-denuded artery rings. The acetylcholine- and GTP-induced relaxations of endothelium-intact rings were attenuated by NG-nitro L-arginine methyl ester (L-NAME, 330 microM) which attenuation was reversed with L-arginine (1 mM). 3. Guanosine (10 microM-1 mM) relaxed both endothelium-intact and -denuded artery rings in a dose-dependent manner. The relaxations were more pronounced in endothelium-intact preparations and were only slightly attenuated by L-NAME (330 microM). 4. ATP (1 microM-1 mM) and adenosine (10 microM-1 mM) dose-dependently relaxed endothelium-intact and -denuded artery rings. The responses were more pronounced in endothelium-intact vascular preparations. 5. GTP (100 microM) and guanosine (100 microM) increased guanosine 3':5'-cyclic monophosphate (cyclic GMP) accumulation in both endothelium-intact and -denuded artery rings corresponding to the relaxations observed. The concentrations of adenosine 3':5'-cyclic monophosphate (cyclic AMP) were not affected. 6. ATP (100 microM) increased cyclic GMP concentration of endothelium-intact artery rings. The concentrations of cyclic AMP were not affected by ATP (100 microM) and adenosine (100 microM) in endothelium-intact and -denuded vascular preparations.(ABSTRACT TRUNCATED AT 250 WORDS)     

Helsinki Heart Study: primary-prevention trial with gemfibrozil in middle-aged men with dyslipidemia. Safety of treatment, changes in risk factors, and incidence of coronary heart disease

In a randomized, double-blind five-year trial, we tested the efficacy of simultaneously elevating serum levels of high-density lipoprotein (HDL) cholesterol and lowering levels of non-HDL cholesterol with gemfibrozil in reducing the risk of coronary heart disease in 4081 asymptomatic middle-aged men (40 to 55 years of age) with primary dyslipidemia (non-HDL cholesterol greater than or equal to 200 mg per deciliter [5.2 mmol per liter] in two consecutive pretreatment measurements). One group (2051 men) received 600 mg of gemfibrozil twice daily, and the other (2030 men) received placebo. Gemfibrozil caused a marked increase in HDL cholesterol and persistent reductions in serum levels of total, low-density lipoprotein (LDL), and non-HDL cholesterol and triglycerides. There were minimal changes in serum lipid levels in the placebo group. The cumulative rate of cardiac end points at five years was 27.3 per 1,000 in the gemfibrozil group and 41.4 per 1,000 in the placebo group--a reduction of 34.0 percent in the incidence of coronary heart disease (95 percent confidence interval, 8.2 to 52.6; P less than 0.02; two-tailed test). The decline in incidence in the gemfibrozil group became evident in the second year and continued throughout the study. There was no difference between the groups in the total death rate, nor did the treatment influence the cancer rates. The results are in accord with two previous trials with different pharmacologic agents and indicate that modification of lipoprotein levels with gemfibrozil reduces the incidence of coronary heart disease in men with dyslipidemia.     

An economic analysis of pancreas transplantation: costs, insurance coverage, and reimbursement

Since 1988 the demand for the pancreas transplantation has continued to increase. This has been accompanied by a growth in the number of centers offering the procedure, and an increase in the number of transplants performed. The National Cooperative Transplantation Study was undertaken to document the costs of all transplants, including pancreas transplantation. Data on transplantation procedure charges, from date of transplant to discharge, were obtained from 66.7% of all pancreas transplantation programs active in 1988. These programs accounted for 72% of all transplants performed that year. Valid sample survey data (no more than 25 transplants per center) were obtained for 133 randomly selected patients. This constituted 54% of all procedures done in the United States in 1988. Detailed data were also collected on sources of payment and amount reimbursed. Due to outlier data, we report statistical medians, rather than means, as our measure of central tendency. The median charge for a pancreas transplant with or without a kidney was $66917, with a hospital length of stay of 21 days, compared with a kidney transplant alone at $39625 and a hospital length of stay of 14 days. Total pancreas transplant charges fell between $45260 and $105375 for 50% of the cases studied. Half of the patients had a hospital length of stay between 16 and 33. Due to the small number of cases available for analysis, it was not meaningful to cross-classify the data according to various prognostic variables.(ABSTRACT TRUNCATED AT 250 WORDS)     

Perioperative monitoring of the electrocardiogram during cerebral aneurysm surgery

Electrocardiographic (ECG) abnormalities occur frequently following a subarachnoid hemorrhage and may also occur intraoperatively and postoperatively in patients undergoing neurovascular procedures. The aim of this study was to assess the relationship between ECG changes and the neurological status of the patient, the size and the location of the aneurysm, and the influence of these changes on the cardiac and neurological outcome. The preoperative ECG was analyzed in 270 patients. Forty-five patients had intraoperative Holter monitoring. An immediate postoperative ECG was recorded in 120 patients and 60 patients had three consecutive postoperative ECGs. Preoperatively, 52% of the patients had an abnormal ECG and the incidence was highest in patients with a poorer neurological status. Most of the ECG changes involved the T wave or the ST segment. Intraoperative and postoperative changes occurred in 35 and 65% of the patients, respectively, and were independent of the studied factors. There were no documented cardiac events. The presence of an abnormal preoperative ECG did not influence the neurological outcome of the patient, but fluctuating postoperative changes were associated with a worse outcome.     

Urinary arginine and ornithine in occupational exposure to 2-ethylhexanoic acid

Nine sawmill workers were divided into two groups according to their exposure to 2-ethylhexanoic acid, (EHA), a pesticide which has replaced the older pentochlorophenol. The men with lower exposure excreted 30±10 nmol EHA/mmol creatinine (mean ±SD,n=4) in urine samples taken after the workshift, whereas men with higher exposure excreted 1.8±1.6 mol EHA/mmol creatinine (mean±SD,n=5,p<0.01). The urinary ornithine and arginine concentrations were at the lower exposure 1.4±0.4 and 1.5±0.8 mol/mmol creatinine, respectively (mean±SD,n=4), and they increased significantly (p<0.01) to 4.5±2.5 and 3.2±1.5mol/mmol (mean±SD,n=5), respectively, at the higher exposure. This might have been caused by the inhibitory effect of EHA on urea synthesis which was partially compensated for by elevated arginine and ornithine concentrations to drive the urea cycle more efficiently.     

Intravascular ultrasound in interventional radiology

Intravascular ultrasound (IVUS) imaging provides useful additional information to X-ray angiography in selected cases of balloon angioplasty and stent placement with complex vascular anatomy and unclear findings at angiography. It facilitates accurate measurements of the vessel dimensions and reveals the extent of the disease for the selection of proper angioplasty balloon size, as well as confirms full expansion and attachment of the stent or stent graft to the arterial wall. Intravascular US imaging contributes useful information for the basis of planning surgical or endovascular therapy of aortic dissection and is valuable for guiding percutaneous fenestration of the dissection flap. This imaging modality facilitates placement of vena cava filter without cavography and/or fluoroscopy in patients with contraindication for iodine contrast media and/or X-ray fluoroscopy. Technical development may further increase utility of IVUS imaging in interventional radiology. Received: 22 May 2000; Accepted: 7 June 2000     

Osteoarthritis of finger joints in Finns aged 30 or over: prevalence,determinants, and association with mortality

BACKGROUND: Prevalence and risk factors of osteoarthritis (OA) in finger joints have been amply explored in previous studies. However, no study has focused on finger joint OA as a predictor of mortality. OBJECTIVE: To investigate finger joint OA for its associations with alleged risk factors and with life expectancy in an extensive health survey. METHODS: From 1978 to 1980 a representative population sample of 8000 Finns aged 30 years or over was invited to participate in a comprehensive health examination; 90% accepted. Hand radiographs were taken from 3595 subjects. By the end of 1994, 897 of these had died. RESULTS: The prevalence of OA of Kellgren's grade 2 to 4 in any finger joint and in at least two symmetrical pairs of distal interphalangeal joints (DIPs) was 44.8% and 16.0%, respectively. Age and body mass index were significant determinants for OA both in any finger joint and in symmetrical DIP OA. The history of physical workload in women showed a positive association with OA in any finger joint. Smoking in men seemed to protect against symmetrical DIP OA. As adjusted for the determinants above, symmetrical DIP OA predicted mortality in women (relative risk (RR), 1.23; 95% confidence interval (95% CI) 1.01 to 1.51), but not in men (RR 0.89; 95% CI 0.68 to 1.16). In men, however, OA in any finger joint significantly predicted cardiovascular deaths (RR 1.42; 95% CI 1.05 to 1.92). CONCLUSION: OA in any finger joint and symmetrical DIP OA have different risk factor profiles and predict mortality in different patterns between men and women.