- CSR Baker, LRI Baker (Dept.of Cardiology, UK, St.Bartholemew’s Hospital UK)
Editorial – Prevention of contrast nephropathy after cardiac catheterisation.
Heart 2001; 85:361-362
Increasing number of patients are now being exposed to contrast medium for various investigational procedures and the problem of radiocontrast induced nephropathy assumes greater and greater importance (RCIN).
This has now become the third most common cause of new onset renal failure in hospital patients. Patients, most at risk are those with impaired renal function as judged by an increase in serum creatinine concentration. Diabetes further amplifies the risk.
The volume of contrast medium is also important and the risk of renal failure rises with the dose of 100ml with contrast medium.
The typical patients with RCIN is non-oliguric. Most patients recover but minority become dialysis dependent. To reduce the risk of development of RCIN, patients with high serum creatinine (indicative of reduction in glomerullar filtration rate) should be prehydrated before exposure to contrast medium.
- Cirit M, Ozkahya M, Soydas Cinar C, et al (Ege Univ, Izmir, Turkey)
Disappearance of Mitral and Tricuspid Regurgitation in Haemodialysis Patients After Ultrafiltration
Nephrol Dial Transplant 13: 389-392, 1998
Patients with valvular regurgitation who are undergoing dialysis have a poor prognosis. Controlling the resulting volume overload and cardiac dilatation with ultrafiltration may reduce the functional aggravation.
In 21 patients (9 females) undergoing haemodialysis, Doppler echocardiography detected mitral and tricuspid regurgitation. All patients received intensified ultrafiltration (UF) during dialysis until blood pressure and heart size became normal.
After UF regurgitation improved in all, mitral regurgitation disappeared in 13 and tricuspid regurgitation disappeared in 14. Significant changes also occurred in other parameters, such as mean arterial blood pressure, heart size, left atrial and ventricular pressures and diameters of mitral annulus; left ventricular ejection fraction increased after treatment in all patients but remained below 50% in 11 patients.
Ultrafiltration in dialysis patients can ameliorate valvular regurgitation and significantly improve cardiac dimensions and blood pressure.
- M. Boaz, S Smetana, et al
Secondary prevention with antioxidants of cardiovascular disease in endstage renal disease (SPACE): randomised placebo-controlled trial.
The Lancet, vol.356; Oct.7, 2000: 1213-18.
Excess cardiovascular mortality has been documented in chronic haemodialysis patients. Oxidative stress is greater in haemodialysis patients with prevalent cardiovascular disease than in those without, suggesting a role for oxidative stress in excess cardiovascular disease in haemodialysis. The authors investigated the effect of high-dose vitamin E supplementation on cardiovascular disease outcomes in haemodialysis patients with pre-existing cardiovascular disease.
In haemodialysis patients with prevalent cardiovascular disease, supplementation with 800 IU/day vitamin E reduces composite cardiovascular disease endpoints and myocardial infarction.
- Robert M Streiter, John A Belperio
Chemokine receptor polymorphism in transplantation immunology: no longer just important in AIDS.
Lancet, vol.357, June 2, 2001, pg.1725
AIDS-related research has linked the importance of the biology of chemokine ligands and receptors to HIV-1 susceptibility. An important discovery is that a natural mutation of a receptor for chemokines belonging to the CC family, CCR5, confers on individuals who are homozygous for the expression of the mutant allele CCR5?32 high resistance to HIV-1 infection.
This study shows that the molecular genetics of a chemokine-receptor polymorphism can behave as a major determinant for long-term allograft survival, and provides important insight into the prognosis and genetic susceptibility for functional loss of allografts. Recent investigations have also identified interactions between other chemokine receptors and ligands (i.e., CCRI and CXCR3) that profoundly predispose to allograft rejection. Therefore, the critical role of chemokine biology in transplantation immunology is expanding. Such expansion should pave the way for the development of pharmaceutical agents that will target pathogenetic steps in chemokine biology and provide new treatments that will ultimately enhance long-term allograft survival.
- David Chadwick
Commentary – Vagal nerve stimulation for epilepsy
Lancet, vol.357, June 2, 2001, pg.1726
Vagal-nerve stimulation (VNS) stops strychnine-induced seizures in dogs and pentylenetetrazol-induced seizures in rats. Chronic stimulation of the vagal nerve reduces the frequency of spontaneous seizures in monkeys with alumina-gel foci. The device consists of a pulse generator, a bipolar lead to stimulate the nerve, and a programming wand and software with handheld magnets capable of switching the stimulator on or off. The device is implanted to stimulate the left, rather than the right, vagal nerve, since stimulation on this side is less likely to cause cardiac effects.
This new technology has been well publicized in the media as an alternative to an increase in antiepileptic drugs in patients with chronic refractory epilepsy. The device can be easily implanted as a day-case procedure.
Current device shows that VNS has an unequivocal although modest therapeutic effect against complex partial seizures. A more complete understanding of VNS across the disorder of epilepsy is needed before its contribution to care can be assessed.
- Robert S. Rosenson (Northwestern University Medical School, Preventive Cardiology Center, Division of Cardiology, Chicago, U.S.A.)
Lipid Lowering Therapy as an Important Adjunct to Stroke Prevention in Coronary Heart Disease Patients
Drugs of Today, Vol. 37(11), November 2001, Pg. 731-738
Lipid altering pharmacotherapy has been shown to reduce stroke in coronary heart disease (CHD) patients. Several mechanisms of cerebrovascular protection attributed to these agents include reduction in embolic stroke from cardiac, aortic and carotid sites, delayed progression of carotid stenoses, stabilization of vulnerable carotid atherosclerotic plaque and improvement in cerebral blood flow.
Hypercholesterolemia has not been considered an important risk factor for stroke. Nevertheless, clinical trials of lipid altering pharmacotherapies in CHD patients have been accompanied by reductions in strokes and/or transient cerebral ischemia and the need for carotid endarterectomy.
Retrospective analysis of clinical trials in CHD patients demonstrates that lipid lowering therapy (statins, nicotinic acid and fibric acid derivatives) reduce stroke and transient ischemic attacks. Until prospective clinical trials of stroke prevention are completed in subjects without established CHD, prevention of further myocardial damage with lipid lowering therapies will decrease left ventricular dysfunction, mural thrombus and cardioembolic stroke.
Statins delay progression of carotid atherosclerosis, stabilize carotid atherosclerotic plaque and reduce the propensity for plaque rupture, an important distinguishing feature in symptomatic carotid artery disease and rapid growth of atherosclerotic lesions.
Lipid altering pharmacotherapy should be used for long-term preventive therapy in the stroke-prone patient. In experimental animal studies, statin therapy has a beneficial effect in acute stroke through NO mediated improvement in cerebral blood flow and consequent reduction in stroke size and less neurological deficits.
It remains to be determined whether lipid-altering therapies prevent stroke or limit cerebral infarction and neurological deficits in humans at high risk for stroke.