Refining the Approach to Renal Artery Revascularization

Renal artery stenosis (RAS) is caused by a heterogenous group of diseases with different pathophysiology, clinical manifestations, treatment approaches, and outcomes. The 2 most common forms of RAS are fibromuscular dysplasia (FMD) and atherosclerosis (ARAS). Renovascular syndromes are broadly classified into renovascular hypertension and ischemic nephropathy, but these terms are misleading, because they imply a causal relationship between RAS, hypertension, and renal dysfunction, which is difficult to prove in humans. Data supporting renal revascularization are limited by heterogeneous causes of hypertension and renal dysfunction, insufficient understanding of the relationship between RAS and nephropathy, inconsistent techniques for revascularization, ambiguous terminology and end points to assess benefit, and lack of large-scale randomized trials. The purpose of this review is to enhance understanding of the epidemiology, clinical markers, and diagnosis of RAS; the relationship between RAS and important disease states; the distinction between renal ischemia and nephropathy; optimal revascularization techniques; and avoidance of renal injury

Comparative results of transluminal extraction coronary atherectomy in saphenous vein graft lesions with and without thrombus

AbstractObjectives. The purpose of this retrospective study was to compare the results of transluminal extraction coronary atherectomy in saphenous vein graft lesions with and without angiographic thrombus.Background. Percutaneous interventions in lesions with thrombus are associated with reduced procedural success and increased risk of complications. Use of the transluminal extraction catheter, which cuts and aspirates atheroma and thrombus, has been advocated as a potential revascularization strategy for lesions with thrombus.Methods. Baseline patient characteristics, lesion morphology, immediate angiographic results, in-hospital complications and follow-up were prospectively entered into an interventional cardiology data base. The results of transluminal extraction coronary atherectomy in saphenous vein bypass grafts with angiographic thrombus were compared with results in similar grafts without angiographic thrombus.Results. Transluminal extraction coronary atherectomy was performed in 175 patients with 183 vein graft lesions, including 59 lesions (32%) with thrombus (Group 1) and 124 (68%) without thrombus (Group 2). Compared with lesions in Group 2, lesions in Group 1 were associated with a higher incidence of baseline total occlusion, diffuse disease and abnormal Thrombolysis in Myocardial Infarction (TIMI) grade flow (p < 0.05); more severe diameter stenosis at baseline, after atherectomy and after final angiography (p < 0.05); a lower rate of clinical success (69% vs, 88%, p < 0.01); and more angiographic and clinical complications, including no reflow (p < 0.05), vascular repair (p < 0.05) and Q wave myocardial infarction (p = 0.09).Conclusions. In transluminal extraction coronary atherectomy of saphenous vein bypass grafts, the presence of thrombus is associated with more baseline lesion complexity, reduced clinical success and increased risk of no reflow, Q wave myocardial infarction and vascular repair

Balloon dilation of mitral stenosis in adult patients: Postmortem and percutaneous mitral valvuloplasty studies

Preliminary reports have documented the utility of percutaneous balloon valvuloplasty of the mitral valve in adult patients with mitral stenosis, but the mechanism of successful valve dilation and the effect of mitral valvuloplasty on cardiac performance have not been studied in detail. Accordingly, mitral valvuloplasty was performed in five postmortem specimens and in 18 adult patients with rheumatic mitral stenosis, using either one (25 mm) or two (18 and 20 mm) dilation balloons. Postmortem balloon dilation resulted in increased valve orifice area in all five postmortem specimens, secondary to separation of fused commissures and fracture of nodular calcium within the mitral leaflets. In no case did balloon dilation result in tearing of valve leaflets, disruption of the mitral ring or liberation of potentially embolic debris.Percutaneous mitral valvuloplasty in 18 patients with severe mitral stenosis (including 9 with a heavily calcified valve) resulted in an increase in cardiac output (4.3 ± 1.1 to 5.1 ± 1.5 liters/min, p < 0.01) and mitral valve area (0.9 ± 0.2 to 1.6 ± 0.4 cm2, p < 0.0001), and a decrease in mean mitral pressure gradient (15 ± 5 to 9 ± 4 mm Hg, p < 0.0001), pulmonary capillary wedge pressure (23 ± 7 to 18 ± 7 mm Hg, p < 0.0001) and mean pulmonary artery pressure (36 ± 12 to 33 ± 12 mm Hg, p < 0.01). Left ventriculography before and after valvuloplasty in 14 of the 18 patients showed a mild (≤1 +) increase in mitral regurgitation in five patients and no change in the remainder. Embolic phenomena were not observed in any patient.Serial radionuclide ventriculography showed an increase in left ventricular peak filling rate (2.20 ± 1.20 to 2.50 ± 1.20 end-diastolic volumes per second [EDV/s], p < 0.05). Serial echocardiography/phonocardiography showed improvement in mitral valve excursion (11 ± 6 to 14 ± 6 mm, p < 0.001), mitral EF slope (7 ± 4 to 13 ± 5, p < 0.001), left atrial diameter (5.7 ± 0.9 to 5.3 ± 0.8 cm, p < 0.001), S2-opening snap interval (0.07 ± 0.03 to 0.08 ± 0.02 second, p < 0.02) and mitral valve area (0.9 ± 0.2 to 1.5 ± 0.4 cm2, p < 0.0001). All patients were discharged from the hospital with de- creased symptoms after valvuloplasty.It is concluded that percutaneous mitral valvuloplasty can be performed in adult patients with mitral stenosis, including patients with calcific disease, and can result in significant improvement in valvular function. The mechanisms of successful dilation include commissural separation and fracture of nodular calcium

A global phylogeny of butterflies reveals their evolutionary history, ancestral hosts and biogeographic origins

Butterflies are a diverse and charismatic insect group that are thought to have evolved with plants and dispersed throughout the world in response to key geological events. However, these hypotheses have not been extensively tested because a comprehensive phylogenetic framework and datasets for butterfly larval hosts and global distributions are lacking. We sequenced 391 genes from nearly 2,300 butterfly species, sampled from 90 countries and 28 specimen collections, to reconstruct a new phylogenomic tree of butterflies representing 92% of all genera. Our phylogeny has strong support for nearly all nodes and demonstrates that at least 36 butterfly tribes require reclassification. Divergence time analyses imply an origin similar to 100 million years ago for butterflies and indicate that all but one family were present before the K/Pg extinction event. We aggregated larval host datasets and global distribution records and found that butterflies are likely to have first fed on Fabaceae and originated in what is now the Americas. Soon after the Cretaceous Thermal Maximum, butterflies crossed Beringia and diversified in the Palaeotropics. Our results also reveal that most butterfly species are specialists that feed on only one larval host plant family. However, generalist butterflies that consume two or more plant families usually feed on closely related plants

Necessity (darura) in Islamic law : a study with special reference to the Harm Reduction Programme in Malaysia

This study serves two aims, to shed light on the rule of darura in Islamic law and to examine the justification for the Harm Reduction Programme in Malaysia using the said rule. In an attempt to fathom the real understanding of this rule, I have employed two methods: a critical approach to the darura theoretical discussions and an analysis of darura cases presented in fiqhi treatises. The study demonstrates that the usuliyun have formulated a narrow scope of darura theory although the applications of the rule in fiqhi treatises suggest other ways in which the principle can be applied. The jurists tend to apply the rule in a much wider sense in the various fiqhi works, either in true and factual cases or in hypothetical ones. This research also finds that the modern jurists have expanded the application not only to protect the necessity of an individual person but to protect the necessity of the public at large. It can also be suggested that the rule of darura has provided measures derogating obligations; however, this must only be to the extent required by the exigencies of the situation. A rigorous understanding of this rule is crucial for the field of Islamic law in order to avoid any possible abuse. Based on the above understanding of darura, this study finally investigates whether darura can justify the Harm Reduction Programme in Malaysia. This programme has been promulgated to reduce HIV/AIDS cases by providing drug users with methadone, syringes and needles. The programme was assessed thoroughly using the legal requirements and preconditions of darura. Having examined the philosophy, its modus operandi and jurists' attitude towards drugs, the study concludes that this programme is justified from a shari`a perspective on the basis of necessity. However, strict precautions and regulations need to be continuously employed throughout this controlled programme to avoid any abuse which might impair its legality. The research also aims to enhance the public's understanding of the rule of darura and to improve the collaboration between Malaysian government and religious groups in minimising HIV/AIDS and drug cases in Malaysia.EThOS - Electronic Theses Online ServiceGBUnited Kingdo