Expanded infectious diseases screening program for Hispanic transplant candidates.

Most guidelines for pre-transplant screening recommend enhanced screening among patients with potential exposure to such pathogens as Strongyloides stercoralis and Trypanosoma cruzi, the cause of Chagas disease. The incidence of these diseases in the Hispanic immigrant population has not been extensively studied. Transplant candidates who were evaluated by our program's Hispanic Transplant Program were referred for expanded infectious disease screening including Mycobacterium tuberculosis, S. stercoralis, Leishmania, and T. cruzi. Between December 2006 and December 2008, 83 patients were screened. Most were from Mexico but we also screened patients from Ecuador, Puerto Rico, and Peru. Most patients lived in urban locations before moving to the United States. Latent tuberculosis infection (LTBI) was found in 20%, and 6.7% had serologic evidence of S. stercoralis infection. These patients underwent treatment of latent infection without difficulty. To date, 14 patients have undergone living-donor kidney transplantation. Two of these patients had positive Leishmania titers and are being followed clinically, 1 was treated for S. stercoralis, and 2 were treated for LTBI pre-transplant. All have done well without evidence of screened pathogens an average of 348 days (range 65-766 days) post transplant. Expanded screening identifies endemic infections in the Hispanic immigrant population that can be treated before transplant, thereby minimizing post-transplant infectious complications.

Comparison of chronic neutral endopeptidase inhibition and furosemide in an ovine model of heart failure.

The hemodynamic, hormonal, and metabolic effects of chronic neutral endopeptidase (NEP) 24.11 inhibition and furosemide were compared in the pacing model of ovine heart failure (HF). Intravenous SCH 39370 induced a dose-related inhibition of NEP activity during 4-days treatment, in association with a transient increase in plasma atrial natriuretic peptide (ANP) and, at the higher dose, an increased mean level of plasma cyclic guanosine monophosphate. There was a significant and persistent decrease in left atrial pressure, a brief increase in cardiac output (CO), and a tendency for arterial pressure to be reduced. Significant dose-related diuresis and natriuresis were also observed. Furosemide induced a similar hemodynamic response, associated with greater diuresis and natriuresis. Both agents significantly reduced plasma aldosterone levels. Coinfusion of captopril on day 4 of treatment resulted in similar responses in both the SCH 39370- and furosemide pretreated groups. Chronic NEP inhibition significantly alters circulatory and renal function and appears to be as effective as furosemide in reducing cardiac preload in this model of congestive HF.

Drug treatment associated with heart valve replacement.

This article reviews a number of specific pharmacological considerations for patients with prosthetic heart valves. All patients with mechanical heart valves should be anticoagulated. In the past, an International Normalised Ratio (INR) of 2.5 to 4.5 has been recommended. Recent nonrandomised studies have suggested that a patient with a prosthetic valve who is at low risk for thromboembolic events could have an INR ranging from 1.8 to 3.5. The lower end of this range should only be used for patients at higher than average risk of haemorrhage, until randomised data show that levels below 2.5 may be applied universally. In high-risk patients (particularly those with previous thromboembolic events) low dose aspirin should be added. During noncardiac surgery, a patient at low risk for thromboembolic events could be managed by discontinuing anticoagulation 3 days before the operation, with warfarin recommenced as soon as possible afterwards. Perioperative heparinisation would be appropriate in a higher risk patient. Women with prosthetic heart valves wishing to become pregnant should be converted to the use of twice-daily subcutaneous heparin injections. Patients with bioprosthetic valves can be managed without anticoagulation unless they have some other reason to require it. Patients at high risk should be treated with aspirin or warfarin. Thrombolytic therapy for acute valve thrombosis should be used for those who are haemodynamically compromised and therefore have a high risk of mortality from operative intervention. All patients with prosthetic heart valves undergoing invasive procedures potentially causing bacteraemia should receive antibiotic prophylaxis for endocarditis. The actual drugs used depend on the likely nature of the bacteraemia, and any possible patient hypersensitivity.

Small bowel ischaemia in Fabry's disease.

A patient with previously diagnosed Fabry's disease and a long history of post-prandial abdominal pain died following small bowel infarction. Post-mortem demonstrated Fabry's type deposits in the small vessels and nerves supplying the bowel but in addition, a localized atheromatous stenosis of the superior mesenteric artery. In retrospect, his terminal illness and possibly his chronic symptoms were related to the latter finding. Angioplasty to the superior mesenteric artery may have been of benefit. Mesenteric angiography should be considered in patients with chronic post-prandial pain because large vessel disease may coexist with other a priori pathologies and is imminently treatable.

Audit of prioritisation for coronary revascularisation procedures: implications for rationing.

OBJECTIVE: to audit prioritisation of patients awaiting coronary revascularisation. DESIGN: the case records of 92 Christchurch patients referred for coronary artery bypass surgery (CABG) or percutaneous transluminal angioplasty (PTCA) from January to April 1990 were reviewed. The actual waiting time was compared with a nominally optimal waiting time, determined from an urgency rating score based primarily on severity of angina and coronary anatomy. RESULTS: of 56 patients referred for CABG, 47 had left main or multivessel disease including proximal stenosis of the left anterior descending artery. Fifty had Canadian class III or IV angina and 18 had impaired left ventricular function. At the time of review (January 1991), 16 had not yet had an operation. The mean waiting time was at least 163 (SD 116) days. Only nine (16%) had CABG within the maximum optimal time. Thirty-six patients had PTCA within eight months, mean waiting time 80 (53) days. These patients had less severe disease, but similar severity of angina. Nineteen (53%) had their procedure within the optimal period. CONCLUSION: waiting times for coronary revascularisation are excessive, even for high risk patients. Prospective monitoring of the waiting list using a standardised urgency rating score is likely to provide useful information on the dynamics of the waiting list for coronary revascularisation. Furthermore, the effects of further rationing of services can be analysed.

Acute hemodynamic, hormonal, and renal effects of neutral endopeptidase inhibition in ovine heart failure.

The effects of neutral endopeptidase inhibition (NEP-I) were studied in 6 conscious sheep with heart failure (HF) induced by rapid ventricular pacing for 7 days. Measurements were performed 1 h before and for 6 h after intravenous (i.v.) bolus administration of vehicle and SCH 39370 (1.25 and 5 mg/kg) on separate days. After the higher dose, an index of serum NEP activity decreased from 0.83 +/- 0.05 to 0.13 +/- 0.07 nmol/ml/min (p less than 0.001) at 1 h and then returned to control levels at 6 h. Plasma atrial natriuretic peptide (ANP) and cyclic GMP rose from 328 +/- 28 and 20.2 +/- 4.3 to a peak of 570 +/- 65 pmol/L (p less than 0.001) and 28.7 +/- 6.3 nmol/L (p less than 0.05) respectively. Natriuresis and diuresis were significant and left atrial pressure (LAP) decreased from 21.9 +/- 1.1 to 20.1 +/- 0.8 mm Hg (p less than 0.05). Despite high endogenous ANP levels in HF, NEP-I further increases both ANP and its "second messenger." Its natriuretic and hemodynamic effects are consistent with enhanced ANP activity in renal and vascular tissues, suggesting that NEP-I may be useful for treating HF.

An audit of anticoagulation and endocarditis prophylaxis after heart valve surgery.

OBJECTIVE: to audit anticoagulant control and endocarditis prophylaxis following heart valve surgery. DESIGN: retrospective review of all 190 patients living in Canterbury who had heart valve surgery between January 1981 and December 1986 to determine the incidence of endocarditis and complications of anticoagulation. RESULTS: there were 35 late deaths, of which nine were attributed to thromboembolism (3), major bleeding (2), or endocarditis (4). The rate of thromboembolic events, and major bleeding was 4.6 and 3.3/100 patient years of warfarin therapy respectively, while the incidence of late endocarditis was 0.96/100 patient years. Two episodes of endocarditis occurred after minor dental procedures performed without antibiotic prophylaxis. Many dentists indicated that they would not have recommended prophylactic therapy for these procedures. Some patients had inadequate recall of important details of anticoagulant control or endocarditis prophylaxis. Only 24% knew their latest prothrombin ratio, yet a survey of general practitioners revealed that, in their view, the majority of patients may be capable of monitoring their own anticoagulant therapy. CONCLUSION: the incidence of potentially preventable long term complications of heart valve surgery is comparable to other series. Nevertheless, these complications could be reduced by better patient education possibly enhanced by greater involvement of the patient in their anticoagulant control. The indications for antibiotic prophylaxis for dental procedures should be broadened for this group of patients.

Acute thrombotic obstruction of a mitral valve prosthesis: the role of thrombolytic therapy.

An acute thrombotic occlusion of a mitral prosthesis in a hemodynamically compromised patient was successfully lysed with intravenous streptokinase. Unfortunately, the patient had a major cerebral embolus, from which she died several days later. A review of the current literature reveals that thrombolytic therapy successfully relieves the obstructing thrombus in 73% of cases, while it is partially successful in another 16% allowing deferral of surgical repair to a more optimal time. Mortality from thrombolytic therapy is 14% while hemorrhage or cerebral emboli occur in a further 11%. Reports of surgical intervention have shown an operative mortality rate of 25%, in those fit to undergo surgery. If hemodynamically unstable patients unfit for surgery are included on an intention to treat basis, overall mortality is 42%. Thus, thrombolytic therapy should be considered primarily in those compromised patients who have a thrombotic occlusion of a valvular prosthesis with a greater risk of operative mortality. Low dose, prolonged infusions should be favoured over rapid, high concentration infusions currently employed for coronary thrombolysis, as the latter regime could have contributed to the fatal cerebral embolus in our patient.