In KOA patients, hypoalgesia after cold pressor stimulation and aerobic exercise assessed preoperatively by cuff algometry was associated with pain relief 6 months after TKR. EIH as a novel preoperative screening tool should be further investigated in larger studies.

We examined the risk of thrombotic and major bleeding events in patients undergoing total hip and knee replacement (THR and TKR) treated with thromboprophylaxis, using nationwide population-based databases. We identified 83 756 primary procedures performed between 1997 and 2011. The outcomes were symptomatic venous thromboembolism (VTE), myocardial infarction (MI), stroke, death and major bleeding requiring hospitalisation within 90 days of surgery. A total of 1114 (1.3%) and 483 (0.6%) patients experienced VTE and bleeding, respectively. The annual risk of VTE varied between 0.9% and 1.6%, and of bleeding between 0.4% and 0.8%. The risk of VTE and bleeding was unchanged over a 15-year period. A total of 0.7% of patients died within 90 days, with a decrease from 1% in 1997 to 0.6% in 2011 (p < 0.001). A high level of comorbidity and general anaesthesia were strong risk factors for both VTE and bleeding, with no difference between THR and TKR patients. The risk of both MI and stroke was 0.5%, which remained unchanged during the study period. In this cohort study of patients undergoing THR and TKR patients in routine clinical practice, approximately 3% experienced VTE, MI, stroke or bleeding. These risks did not decline during the 15-year study period, but the risk of dying fell substantially.

The renal response to a selective increase in the Na+ concentration of the blood perfusing the central nervous system was investigated in conscious dogs treated with the converting enzyme inhibitor enalaprilat and the aldosterone antagonist canrenoate. In split-infusion experiments the plasma [Na+] of carotid blood was increased (approx. 6 mM) by bilateral infusion of hypertonic NaC1. Concomitantly distilled water was infused into the v. cava making the sum of the infusions isotonic. In control experiments isotonic saline was infused at identical rates into all three catheters. Na+ excretion increased markedly in both series, 103 +/- 14 to 678 +/- 84 mumol min-1 during split-infusion and 90 +2- 14 to 496 +/- 74 mumol min-1 during the isotonic volume expansion. Peak rate of excretion, peak fractional sodium excretion, and cumulative sodium excretion were all significantly higher (P < 0.05) during split-infusion than during control experiments. Plasma vasopressin increased only during split-infusion (0.68 +/- 0.11 to 2.4 +/- 0.8 pg ml-1) while the increases in plasma atrial natriuretic peptide were similar in the two series. Urinary excretion of urodilatin (ANP95-126) increased significantly more during split-infusion (46 +/- 11 to 152 +/- 28 fmol min-1) than during the isotonic volume expansion (45 +/- 14 to 84 +/- 16 fmol min-1) (P < 0.05). It is concluded that the natriuretic mechanisms activated by a selective increase in the Na+ concentration of carotid blood and associated with increased excretion of urodilatin cannot be eliminated by blockade of the renin-angiotensin-aldosterone system.

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