Kulbir Singh

Risk Factors for Abdominal Aortic Aneurysms A 7-Year Prospective Study: The Tromsø Study, 1994–2001

Background— Abdominal aortic aneurysm is an asymptomatic condition with a high mortality rate related to rupture. Methods and Results— In a cohort of 2035 men and 2310 women in Tromsø, Norway, who were 25 to 82 years old in 1994, the authors identified risk factors for incident abdominal aortic aneurysm over the next 7 years. The impact of smoking was studied in particular. Ultrasound examination was performed initially in 1994/1995 and repeated in 2001. There were 119 incident cases of abdominal aortic aneurysms (an incidence of 0.4% per year). Male sex and increasing age were strong risk factors. In addition, the following variables were significantly associated with increased abdominal aortic aneurysm incidence: Smoking (OR=13.72, 95% CI 6.12 to 30.78, comparing current smokers of ≥20 cigarettes/d with never-smokers), hypertension (OR=1.54, 95% CI 1.03 to 2.30), hypercholesterolemia (OR=2.11, 95% CI 1.23 to 3.64, comparing subjects with serum total cholesterol ≥7.55 mmol/L with those with total cholesterol <5.85 mmol/L), and low high-density lipoprotein cholesterol (OR=3.25, 95% CI 1.68 to 6.27, comparing subjects with high-density lipoprotein cholesterol <1.25 mmol/L with those with high-density lipoprotein ≥1.83 mmol/L). In addition, use of statins was associated with increased risk of abdominal aortic aneurysm (OR=3.77, 95% CI 1.45 to 9.81), but this was probably a marker of high risk of cardiovascular diseases. Conclusions— The results demonstrate strong associations between traditional atherosclerosis risk factors and the risk of incident abdominal aortic aneurysms.

Intra- and interobserver variability in ultrasound measurements of abdominal aortic diameter. The Tromsø study

OBJECTIVES To assess the variability of ultrasonographic measurements at different levels of the abdominal aorta. DESIGN Reproducibility study as part of a population health screening for abdominal aortic aneurysm. MATERIALS AND METHODS In 1994/1995 a total of 6892 subjects underwent ultrasound examination of the abdominal aorta. Variability of measurements was assessed in the beginning and end of the survey period by inviting 112 randomly selected participants to a second ultrasound scan within 3 weeks of the first scan. The subjects were examined by an experienced radiologist and three sonographers who had been given a short course in ultrasonography. All examiners were blinded to each others results. RESULTS Variability was similar in the beginning and end of the survey period. Both the intra- and interobserver variability were less than 4 mm for all sonographers in measurements of maximal infrarenal aortic diameter, and variability was similar for measurements in the anterior-posterior and transverse plane. Variability was greater for measurements at the renal level than aortic bifurcation level. The radiologist had lower variability than the other sonographers. CONCLUSION Ultrasound measurements of the maximal diameter can be obtained with a high degree of accuracy. Inexperienced sonographers may achieve acceptable performance given appropriate training and surveillance.

Atherosclerosis in Abdominal Aortic Aneurysms: A Causal Event or a Process Running in Parallel? The Tromsø Study

Objective—The pathogenesis of abdominal aortic aneurysm (AAA) formation is poorly understood. We investigated the relationship between carotid, femoral, and coronary atherosclerosis and abdominal aortic diameter, and whether atherosclerosis was a risk marker for AAA. Methods and Results—Ultrasound of the right carotid artery, the common femoral artery, and the abdominal aorta was performed in 6446 men and women from a general population. The burden of atherosclerosis was assessed as carotid total plaque area, common femoral lumen diameter, and self-reported coronary heart disease. An AAA was defined as maximal infrarenal aortic diameter ≥30 mm. No dose-response relationship was found between carotid atherosclerosis and abdominal aortic diameter <27 mm. However, significantly more atherosclerosis and coronary heart disease was found in aortic diameter ≥27 mm and in AAAs. The age- and sex-adjusted odds ratio (OR) (95% CI) for AAA in the top total plaque area quintile was 2.3 (1.5 to 3.4), as compared with subjects without plaques. The adjusted OR (95% CI) was 1.7 (1.1 to 2.6). No independent association was found between femoral lumen diameter and AAA. Conclusion—The lack of a consistent dose-response relationship between atherosclerosis and abdominal aortic diameter suggests that atherosclerosis may not be a causal event in AAA but develops in parallel with or secondary to aneurismal dilatation.

Catheter‐directed thrombolysis for the management of postpartum deep venous thrombosis

Background.  Catheter‐directed thrombolysis that removes the thrombus and restores patency of the veins appears to be a safe and effective management of acute deep venous thrombosis (DVT). It has been shown to reduce long‐term postthrombotic morbidity and improve the quality of life. Pregnancy and the postpartum period are generally considered as contraindications for thrombolysis. However, catheter‐directed thrombolytic therapy of DVT may reduce long‐term sequelae in these young patients by restoring the patency of veins. The purpose of this pilot study was to evaluate the efficacy of catheter‐directed thrombolysis in treating acute symptomatic postpartum DVT.

Relation of Common Carotid Artery Lumen Diameter to General Arterial Dilating Diathesis and Abdominal Aortic Aneurysms : The Tromso Study

In a cross-sectional, population-based study in Tromsø, Norway, the authors investigated correlations between lumen diameter in the right common carotid artery (CCA) and the diameters of the femoral artery and abdominal aorta and whether CCA lumen diameter was a risk factor for abdominal aortic aneurysm (AAA). Ultrasonography was performed in 6,400 men and women aged 25-84 years during 1994-1995. An AAA was considered present if the aortic diameter at the level of renal arteries was greater than or equal to 35 mm, the infrarenal aortic diameter was greater than or equal to 5 mm larger than the diameter of the level of renal arteries, or a localized dilation of the aorta was present. CCA lumen diameter was positively correlated with abdominal aortic diameter (r = 0.3, P < 0.01) and femoral artery diameter (r = 0.2, P < 0.01). In a multivariable adjusted model, CCA lumen diameter was a significant predictor of AAA in both men and women (for the fifth quintile vs. the third, odds ratios were 1.9 (95% confidence interval: 1.2, 2.9) and 4.1 (95% confidence interval: 1.5, 10.8), respectively). Thus, CCA lumen diameter was positively correlated with femoral and abdominal aortic artery diameter and was an independent risk factor for AAA.

Abdominal aortic aneurysms, or a relatively large diameter of non-aneurysmal aortas, increase total and cardiovascular mortality: the Tromsø study

BACKGROUND In a population-based study in Tromsø, Norway, the authors assessed whether an abdominal aortic aneurysm (AAA) or the maximal infrarenal aortic diameter in a non-aneurismal aorta influence total and cardiovascular disease (CVD) mortality. METHODS A total of 6640 men and women, aged 25-84 years, were included in a 10-year mortality follow-up: 345 subjects with a diagnosed AAA and 6295 subjects with a non-aneurismal aorta. Non-aneurismal aortic diameter and prevalent AAAs were categorized into seven groups. RESULTS In subjects without an AAA, an aortic diameter > or =30 mm increased age- and sex-adjusted total mortality [mortality rate ratio (MRR) = 3.73, 95% confidence interval (CI) 1.77-7.89] and CVD mortality (MRR = 9.24, 95% CI 4.07-20.97) compared with subjects with aortic diameter of 21-23 mm. An AAA at screening was strongly associated with deaths from aortic aneurysm and was associated with total (MRR = 1.60, 95% CI 1.31-1.96) and CVD mortality (MRR = 2.41, 95% CI 1.81-3.21). This was not explained by deaths due to an AAA. Adjustments for CVD risk factors could fully explain the increased total, but not CVD mortality in subjects with an AAA. CONCLUSIONS An AAA increases total and CVD mortality. In the large majority of subjects with a non-aneurysmal aorta, the diameter does not influence total or CVD mortality. However, in individuals with a maximal diameter >26 mm (2% of the population), a positive relationship is found.

Diameter of the Infrarenal Aorta as a Risk Factor for Abdominal Aortic Aneurysm: The Tromsø Study, 1994–2001

OBJECTIVES We aim to study whether the diameter of the non-aneurysmatic infrarenal aorta influences the risk for abdominal aortic aneurysm (AAA) and whether the larger diameter in men can explain the male predominance in AAA. DESIGN This is a population-based follow-up study. MATERIALS AND METHODS In 4265 men and women with a normal-sized aorta in 1994-1995, 116 incident cases of AAA were diagnosed 7 years later. The risk of an incident AAA was analysed in a multiple logistic regression model according to baseline maximal infrarenal aortic diameter, adjusted for known risk factors. RESULTS Compared with subjects with aortic diameter in the 21-23 mm bracket, men and women with a diameter <18mm and > or =27mm had an adjusted odds ratio (OR) of 0.30 (95% confidence interval (CI): 0.10-0.88) and 4.22 (95% CI: 1.94-9.19), respectively, for an incident AAA. When adjusted for age and baseline aortic diameter, male sex was not statistically significantly associated with the incidence of AAA (OR=1.45, 95% CI: 0.93-2.30, P=0.10). CONCLUSIONS Increased baseline diameter of the infrarenal aorta was a highly significant, strong and independent risk factor for developing an AAA. The larger aortic diameter in men than in women may be the most important explanation for the higher AAA risk in men.

Results of catheter-directed endovascular thrombolytic treatment of acute ischaemia of the leg.

OBJECTIVES To observe immediate and late results of catheter-directed endovascular thrombolytic treatment of acute ischaemia of the leg. DESIGN, MATERIAL AND METHODS A total of 212 patients treated with Actilyse® at the University Hospital of North Norway because of acute arterial ischaemia of the leg during the period 01 January 2000-30 June 2006 were analysed retrospectively. RESULTS The radiologic outcome was judged to be successful in 101 (48%), adequate in 80 (38%) and failed in 31 (14%). At 1-year follow-up, 158 (75%) were alive without amputation, 14 (7%) were alive with amputation, 20 (9%) were dead without amputation and 20 (9%) were dead with amputation. Altogether, 34 (16%) were amputated and 40 (19%) were dead after 1 year. After an average observation period of 3.25 years, 111 (52%) were alive without amputation, 16 (8%) were alive with amputation, 60 (28%) were dead without amputation and 25 (12%) were dead with amputation. A total of 41 (19%) were amputated and 85 (40%) were dead. Fifty complications were registered; 30 (14%) patients had a compartment syndrome, eight (4%) had cerebral stroke and 12 (6%) had a myocardial infarction. CONCLUSIONS The results are at least as good as historic controls and similar to international series. Especially, it appears as though the long-term results are somewhat better. The complication rate and morbidity are less than in surgery alone.

Inter-rater agreement between professional-rated and patient-rated scores of the Villalta scale for evaluation of the post-thrombotic syndrome

Within the two years following lower extremity deep vein thrombosis (DVT), between 35 and 56% of cases develop postthrombotic syndrome (PTS) [1–4]. PTS is characterized by eleven possible symptoms and signs, including pain, edema and venous ulcers [5]. PTS is reported to bemoderate to severe in 3–10% of cases, but this can vary to a significant degree within patients during at least the first 2 years after DVT [2]. Consequences of PTS include a reduction of quality of life (QoL) and associated patient and societal economic burdens [6]. The scientific standardization committee of the International Society on Thrombosis and Haemostasis has recommended the Villalta Scale [5] as the gold standard to assess PTS [7]. The Villalta Scale includes a patient-rated symptoms subscale (five items) and professional-rated signs subscale (six items), both assessed at the same time at the outpatient clinic. This reduces the usability of the Villalta Scale in long-term follow-up and clinical trials, as hospital visits can be burdensome and costly. Self-assessment of PTS by patients using the Villalta Scale may be an alternative approach. Recently, Utne et al. (2016) [8] testedwhether visually assisted self-assessment of PTS using the Villalta Scalewas valid and reliable. They found a very good agreement between the self-rated Villalta Scale score and the original (professional-rated) Villalta Scale score. However, this agreement was dependent on a visual aid, developed earlier for trial purposes by Kahn et al. [9], as agreement was only moderate (Kappa 0.60, 95% CI 0.48–0.72) for the selfadministration of the Villalta Scale without this aid. We also assessed inter-rater agreement between self-rated and professional-rated Villalta Scale scores in a retrospective study in which the self-administered Villalta Scale was an unmodified athome-applied questionnaire accompanied by a short written instruction. Consecutive patients who had received catheter-directed thrombolysis (CDT) as treatment for objectively diagnosed iliofemoral DVT at the University Hospital of North Norway (UNN) between January 2002 and January 2012 were eligible. After CDT, treatment proceeded with subcutaneous low-molecular heparin for 5 days or more, overlappingwithwarfarin treatment for at least 6months. Exclusion criteria for treatment with CDT and thus for the current study have been described previously [10]. Patients that agreed to participate were invited for a hospital visit in the first week of April 2013. Two weeks before this visit, we sent the unmodified Villalta Scale with a written instruction to participants by mail. We explained that the symptoms and signs asked for had to be the result of the previously experienced DVT. Technical and medical terms were explained with one word or one sentence using common terms, similar to oral instructions at the outpatient clinic. Patients were asked to return all completed forms by mail. At the outpatient clinic, the Villalta Scale was applied by one

Response to Letters Regarding Article, “Risk Factors for Abdominal Aortic Aneurysms: A 7-Year Prospective Study: The Tromsø Study”

We agree that the question concerning the possibleimpact of statins on the development of abdominal aortic aneurysmsis intriguing. As stated in our article, we cannot conclude from thepresent prospective study whether statin use influences the incidenceof abdominal aortic aneurysm. Thus, a randomized clinical trial isclearly warranted.