Peter Ackrill

Vascular calcification in long-term haemodialysis patients in a single unit: a retrospective analysis.

Vascular calcification (VC), which is described in the elderly and in diabetics, is frequently seen in uraemia. It is usually regarded as having little significance. We studied the roentgenological appearance of VC in a homogeneous group of 38 long-hours haemodialysis patients whose longevity on dialysis allowed sustained (10-25 years) follow-up, including annual skeletal surveys and thrice-yearly clinical examinations and biochemical profiles. We compiled a dossier of clinical and laboratory parameters from the start of dialysis to the present day. We were able to analyze the natural history of VC and to determine which clinical parameters were linked with progression. We found that VC became steadily more prevalent-at dialysis onset present in 39% of the patients, but in 92% after an average dialysis duration of 16 years, with a mean onset 9.7 years after starting dialysis. As well as becoming more prevalent, the calcification became progressively more severe in most patients. There were two patterns of VC: axial (aorta and iliac and femoral arteries), seen alone in 32% of the patients, and peripheral (digital arteries), seen alone in 3% of patients. Most patients (65%) had evidence of both types. Calcification was scored for site and severity. Patient age (r = 0.57, p < 0.001), systolic blood pressure (r = 0.54, p < 0.001), hyperparathyroidism (reduced progression after parathyroidectomy), plasma phosphate (r = 0.34, p = 0.042), and vitamin D concentrations (r = 0.53, p < 0.001) were the principal determinants of severity and rate of progression of VC in this population. There was a weak negative association between progression and serum ferritin (r = -0.33, p = 0.046). The reduced vessel compliance that results from VC is likely to be cardiovascularly deleterious. In severe cases, tissue perfusion or vascular access for haemodialysis can be compromised. VC and accelerated cardiovascular mortality are common to uraemia, diabetes, and systolic hypertension in the elderly. Better understanding of these pathological processes may permit intervention and possibly lead to a reduction in cardiovascular mortality.

Ambulatory blood pressure monitoring in renal dialysis and transplant patients

Blood pressure (BP) elevation and left ventricular hypertrophy are important factors in the high cardiovascular mortality rate in patients on the renal replacement program. Ambulatory BP monitoring is widely regarded as superior to random BP monitoring in predicting end-organ damage from elevated BP. One hundred seventeen patients (60 on hemodialysis [35 with long sessions and 25 with short sessions], 29 on continuous ambulatory peritoneal dialysis, and 28 transplant recipients) underwent ambulatory BP monitoring, with target organ assessment by electrocardiography. Mean 24-hour BP for the patients with the long hemodialysis sessions (LHD) was 115.5/66.6 mm Hg, without the regular use of antihypertensive drugs. The parathormone (PTH) level was the major determinant of BP on ambulatory BP monitoring analysis, with interdialytic weight gain and age each having weaker associations. The BPs of the other three patient cohorts were much higher (short hemodialysis session [SHD], 143.2/82.1 mm Hg; continuous ambulatory peritoneal dialysis, 137.1/76.8 mm Hg; transplant recipients, 135.9/79.2 mm Hg). Overall, two thirds of the patients had reduced diurnal BP variability. Electrocardiogram voltage criteria for left ventricular hypertrophy were exceeded in approximately one third to one half of the patients. Our findings show that good control of BP is possible without recourse to antihypertensive drugs in the context of dialysis with slow ultrafiltration.

Relationships between blood pressure variability and left ventricular parameters in haemodialysis and renal transplant patients

SUMMARY: Blood pressure (BP) elevation and left ventricular hypertrophy (LVH) are important factors in the high cardiovascular mortality on the renal replacement programme. the relationship between these, predictable in essential hypertension, is less well defined in uraemia. We wished to examine the contribution of abnormal blood pressure variability (BPV) to the cardiovascular changes seen in uraemia and after renal transplantation. Twenty‐four hour ambulatory blood pressure monitoring (ABPM), and simultaneous echocardiography, on a cohort of 35 long‐term, long‐hours haemodialysis survivors and 28 patients with stable renal transplants was undertaken. We also retrospectively compiled biochemical and clinical data. There were strong relationships between both diurnal and standard deviation measures of BPV and left ventricular cavity size and function: per cent fall in awake to asleep diastolic BP with fractional shortening index (FSI), r=0.28, P=0.039; with left ventricular mass index (LVMI), r=−0.35, P=0.011. This study suggests that reduced diurnal and short‐term BP variability is cross‐sectionally associated with a dilated, heavier left ventricle (LV) with worse systolic function. Thus, BPV may independently contribute to the abnormal LV structure and function commonly seen in uraemia.

Elective Rather Than Emergency Intervention for Acute Renal Artery Occlusion with Anuria

We describe a case in which surgical revascularisation was electively delayed until 27 days after acute renal artery occlusion, allowing surgery to be performed after a period of haemodialysis and pre-operative cardiac assessment. Owing to the collateral blood supply to the kidney, emergency surgery in cases of acute renal artery occlusion may not be necessary, and may be hazardous.