Francesco Falaschi

Low-density lipoprotein oxidation in essential hypertension.

Objectives: To investigate the occurrence of enhanced low-density lipoprotein (LDL) oxidation as an additional factor promoting atherosclerosis progression in hypertensive patients. Design: The oxidation of plasma LDL was investigated in a group of untreated patients with mild-to-moderate essential hypertension without clinically evident target organ damage and in a group of control subjects. Methods: LDL oxidation was evaluated as both the susceptibility to oxidation in vitro and the presence of plasma anti-oxidized LDL antibodies (as an index for oxidation in vivo). Results: LDL from hypertensive subjects exhibited enhanced susceptibility to oxidation in vitro as revealed by early and accelerated generation of conjugated dienes after exposure to CuSO4. Vitamin E concentration in LDL from hypertensive subjects was slightly but significantly decreased and its efficiency in protecting LDL from oxidation was impaired. Furthermore, a higher plasma anti-oxidized LDL titre was found in hypertensive patients. Subclass analysis revealed that the contemporary presence of hypercholesterolaemia did not significantly modify either the increased susceptibility of LDL to oxidation or the presence of plasma anti-oxidized LDL antibodies detected in hypertensive patients. Moreover, no correlation was found between LDL oxidation parameters and blood pressure values. Conclusions: LDL from hypertensive patients is more susceptible to oxidation in vitro and is more promptly oxidized in vivo. These findings suggest a possible participation of LDL oxidation in promoting and accelerating the atherosclerosis that often develops in hypertensive patients.

Congenital absence of inferior vena cava

Sir—In their report, M Ruggeri and colleagues (Feb 10, p 441) point out the clinical relevance of the congenital absence of the inferior vena cava (IVC) in young patients (<30 years) as a potential independent risk factor for deep vein thrombosis (DVT). In the past 23 months, we have assessed 21 young patients with objectively documented acute venous thromboembolism (15 with isolated DVT, four with isolated pulmonary embolism, and two with DVT and pulmonary embolism). As part of a diagnostic screening in the emergency room, in case of non-compressibility of the common femoral vein, we apply an ultrasonographic investigation of the legs from distal veins to the inferior vena cava (IVC). Because of this approach, aplasia or agenesia of the IVC have been suspected and subsequently confirmed by computed tomography in two cases (9·5% [95% CI 2·7–21·7]). The table shows the clinical characteristics of the patients. Patient 1 had an evident compensatory enlargement of the vena azygos. This patient was referred to us because of signs and symptoms of acute DVT with respiratory failure; perfusion-ventilation lung scanning confirmed the presence of pulmonary embolism. Patient 2 was a young woman who developed bilateral leg swelling in absence of evident risk factors. In these two cases, the mutation for factor V Leiden (G1691A) was diagnosed. The prevalence of the acute IVC in our young population is apparently higher than that reported by Ruggeri and colleagues. Although our approach required computed tomography, only in the case of suspected IVC alterations, this approach seems to be effective for detecting at least an equal number of acute IVC than that detected by routine computed tomography. In conclusion, acute IVC seems to be a not so rare a finding in young patients with confirmed acute venous thormboembolism. Potential advantages of ultrasonography over computed tomography for detecting acute IVC and the weight of congenital thrombophilia in these patients should be investigated in larger series.

Acute Kidney Injury Hyperkalemia in Patients Undergoing Renin-Angiotensin-Aldosterone Blockade

Introduction: In order to minimize the risk of hyperkalemia (hK+) in patients with heart failure (HF), in 2005 and 2009 ACC/AHA (American College of Cardiology; American Heart Association) joint guidelines recommended associating renin-angiotensin system (RAS) inhibition with low-dose ALD-block in patients with serum creatinine (sCr) less than 2.5 mg/dl and serum potassium (sK+) lower than 5 mEq/l. A prevalence of HF in individuals aged 65 and over with mild renal failure at risk of hyperkalemia is steeply increasing. Such data has persuaded us to analyze the association between over-65 HF standard treatment and hK+. Aim: This observational retrospective study analyzed emergency room admissions aged 65 and over undergoing ACEI with ALD-block or potassium sparing diuretics (K+-sparing) and hK+ (sK+ > 6 mEq/l) over a one year period, from January to December 2010. Methods: 8,407 over-65 emergency admissions of 62,348 adult entries have been selected from the hospital database. Data was matched with the Local Medical District pharmaceutical database with joint use of ACEI and ALDblock or K+-sparing medications. Acute Kidney Injury (AKI) was defined according to AKIN (Acute Kidney Injury Criteria) guidelines. Results: ACEI with spironolactone or K+-sparing was found in 332 (3.9%) out of the 8,407 over-65 emergency admissions. Seven HF patients (2.1% aged 79-82, 5F 2M) of 332 had hK+ (sK+, 6.3-8.5 mEq/l). Six patients had spironolactone and 1 K+-sparing treatment. sCr before admission was available in 3 (sCr, 1.1-1.4 mg/dl) out of 7 patients, all of which developed AKI. All 7 patients with hK+ received conservative medical treatment only. Conclusions: hK+ occurred in 7 (2.1%) out of the 332 HF over-65 emergency admissions on ACEI. It might suggest a strict application of the current ACC/AHA guidelines with a closer follow-up for those HF patients at risk of developing AKI and hK+.

RAPID RESPONSE FROM BMJ.COM: How many patients are candidates for home treatment of DVT?

than medical reasons. In our study, only 3% of patients were admitted for medical reasons, and in 9% admission was because medication and international normalised ratio could not be monitored. Even these patients could have been treated as outpatients if adequate professional care had been available at home. No serious complications were noted in patients treated in an outpatient setting. Another 9% of our patients presented in the emergency room and were already being treated for deep vein thrombosis suspected on clinical grounds alone. They were admitted until ultrasound examination could be performed. ✦