A.C.W. Ting

Lipoprotein (a) and its Relationship to Risk Factors and Severity of Atherosclerotic Peripheral Vascular Disease

OBJECTIVES To determine the significance of Lipoprotein (a) (Lp(a)) as a risk factor for atherosclerotic lower limb peripheral vascular disease (PVD), and its relationship to other demographic and biochemical variables and disease pattern and severity. DESIGN Prospective case-control study. MATERIAL AND METHODS Demographic and biochemical risk factors, lipoprotein fractions and Lp(a) were measured in 200 patients with PVD and 200 age- and sex-matched control subjects. Lp(a) levels were correlated with traditional risk factors and clinical and vascular laboratory disease parameters. RESULTS Patients with PVD have a higher incidence of smoking, hypertension, and diabetes mellitus; and had significantly higher levels of serum cholesterol, triglycerides, LDL, VLDL, apolipoprotein B, fasting glucose, fibrinogen, plasminogen, haematocrit, white cell and platelet counts; but lower levels of HDL and apolipoprotein A1. Fasting Lp (a) concentration is an independent risk factor for PVD and is significantly higher in the patients (median = 26.1 mg/dl [4.8-195], mean = 36.5 +/- 32.6 mg/dl) than in controls (median = 18.2 mg/dl [5.4-216], mean = 27.2 +/- 28.1 mg/dl; p < 0.0001). In patients with PVD, Lp(a) correlated positively with plasma LDL, cholesterol, fibrinogen, renal disease, and apolipoprotein B. Fasting levels of > 24 mg/dl incurred a two-fold increase in risk of PVD. Patients with a higher Lp(a) have a significantly higher incidence of resting pain and ulcerations, and regression analysis confirmed smoking and Lp(a) level to be associated with the SVS category of disease severity. CONCLUSIONS Lipoprotein (a) is a significant independent risk factor for PVD. Lp(a) levels correlated with LDL, cholesterol, fibrinogen, apolipoprotein B and disease severity. An elevated Lp(a) level may be associated with more severe forms of PVD.

Screening for asymptomatic carotid stenosis in patients with peripheral vascular disease: a prospective study and risk factor analysis.

Screening for asymptomatic carotid artery stenosis using color flow duplex scan was performed on 186 Chinese patients with peripheral vascular disease. They consist of 121 male and 65 females, with a mean age of 70.6 years. A carotid bruit was present in 43 (23.1%) of the patients. Internal carotid artery stenosis of 70% or greater was detected in 46 patients (24.7%) including six total occlusions. Another 79 patients (42.5%) had internal carotid artery stenosis in the 30-69% range. Significant internal carotid artery stenosis was associated with age, male sex, the quantity and duration of smoking and a carotid bruit, and inversely with cholesterol, triglyceride and VLDL. Age, the number of cigarettes consumed per day, and carotid bruit were independent significant predictors of > or =70% internal carotid artery stenosis on logistic regression analysis. The degree of internal carotid artery stenosis is more severe in patients with a carotid bruit, and correlated positively with age (P<0.01), the number of cigarettes smoked (P = 0.04), and the duration of smoking (P = 0.03). Multiple linear regression analysis showed that only the age of the patient bears a significant relationship with the degree of internal carotid artery stenosis (P<0.01). There was no relationship between the degree of lower limb ischemia with carotid stenosis. The prevalence of > or =70% internal carotid artery stenosis in a high risk population with peripheral vascular disease was 24.7%. Routine duplex screening is worthwhile in this group of patients, particularly in male, elderly smokers.

Laparoscopic transperitoneal clipping of the inferior mesenteric artery for the management of type II endoleak after endovascular repair of an aneurysm

We report the case of a high risk patient with an abdominal infrarenal aortic aneurysm (AAA) who was treated by endovascular technique and the subsequent management of a type II endoleak by the laparoscopic approach. In this case, a 74-year-old woman with a 6-cm infrarenal AAA underwent endovascular repair using a bifurcated stent-graft device. Surveillance CT scan showed a persistent type II endoleak at 1 week and 3 months after the operation. Angiography confirmed retrograde flow from the inferior mesenteric artery (IMA). Attempted transarterial embolization of the IMA via the superior mesenteric artery was not successful. Laparoscopic transperitoneal IMA clipping was performed. Subsequent aortic duplex scan and CT scan confirmed complete elimination of the type II endoleak. We conclude that a combination of endovascular and laparoscopic procedures can be used to manage AAA successfully.

Clinical outcomes and changes in venous hemodynamics after subfascial endoscopic perforating vein surgery

Background: We evaluated the clinical results of subfascial endoscopic perforating vein surgery (SEPS) in patients with severe chronic venous insufficiency (CVI) (clinical class 4–6) and assessed the hemodynamic changes associated with SEPS using air plethysmography (APG). Methods: Forty-five patients with severe CVI who had undergone SEPS were evaluated. Clinical score and venous hemodynamics, as measured by APG before operation and at 1 month and 1 year after operation, were compared using the Wilcoxon signed rank test. Patient satisfaction (on a visual analogue scale of 0 to 100%) was also assessed. Results: There were 29 men and 16 women; their mean age was 60 years (range, 37–83). Thirty-five patients (78%) had active venous ulcers; the ulcers’ mean size was 7.8 ± 11.9 cm2 and the mean duration of ulceration was 9 ± 10 months. There were no hospital deaths. Postoperative complications were uncommon (one groin wound infection and one case of thrombophlebitis). At a mean follow-up of 15 ± 9 months, 34 ulcers (97%) had healed. The cumulative ulcer healing was 82% at 3 months. There were five recurrent ulcers (15%). Significant improvement was seen in the clinical scores (10 ± 3 before operation, 6 ± 4 at 1 month, and 4 ± 3 at 1 year after operation). The venous filling index was also significantly improved after operation; this improvement was maintained at 1-year follow-up (7.36 ± 6.23 ml/sec before operation, 3.63 ± 3.90 ml/sec at 1 month, and 3.14 ± 2.06 ml/sec at 1 year). The degree of patient satisfaction was also remarkable, with 74 ± 17% and 90 ± 12% satisfaction at 1-month and 1-year follow-up, respectively. Conclusions: SEPS is a safe and effective treatment for patients with severe CVI. It leads to hemodynamic improvement, with rapid ulcer healing, and it is associated with a high degree of patient satisfaction.

Ex-vivo Haemodynamic Models for the Study of Stanford Type B Aortic Dissection in Isolated Porcine Aorta

OBJECTIVES The aim of this study is to present novel ex-vivo models in the study of complex haemodynamical changes in Stanford type B aortic dissection (TBAD). MATERIALS AND METHODS Fifteen fresh porcine aortas were harvested and preserved with 4 °C saline. Ex-vivo models were developed to simulate TBAD in three different situations: model A with patent false lumen, model B with distal re-entry only and model C with proximal primary entry only. These models were connected to standardised pulsatile pumps and the pressure waveforms were monitored and compared. The aortas were scanned with ultrasonography and subjected to post-experiment autopsy. RESULTS The three different models were successfully created (n = 13). Pulsatile flow testing was successful and the shapes of the pressure waveforms were similar to those taken from human aorta. Post-testing gross examination confirmed the success of modelling. CONCLUSION Porcine aortas may prove to be useful ex-vivo models in the study of aortic dissection haemodynamics. These models are reproducible and may be used in the study of complex haemodynamic forces during the development and propagation of TBAD. Our three porcine models give a potential possibility in helping clinicians isolate and analyse complex haemodynamical factors in the development, propagation and prognosis of TBAD.

Bleeding peptic ulcer: an evolving role for surgical intervention

Early surgical intervention was previously advocated in patients > 60 years with bleeding peptic ulcer presenting with haemodynamic instability or ongoing transfusion requirements. It is, however, well recognized that emergency surgical intervention with its inherent risks must be reserved for highly selected patients in whom endoscopy initially fails to control exsanquinating haemorrhage or in whom life‐threatening bleeding recurs. Therapeutic endoscopy for bleeding ulcer has led to a remarkable decline in rebleeding rates, the need for emergency surgery and mortality. Octogenarians are at risk, particularly when ulcer size exceeds 2 cm. Poor surgical candidates make up two‐thirds of patients with major ulcer bleeding and operation is to be avoided if at all possible. Medical therapy with proton pump inhibitor and subsequent eradication of Helicobacter pylori following endoscopic treatment has been shown to be beneficial to outcomes. Should surgery be deemed necessary, it is likely that laparoscopic techniques to control bleeding, with or without the addition of an acid‐reducing procedure, will find a role in haemodynamically stable patients undergoing operation on an early elective basis.