Blood Vessel Disease and Vascular Surgery
Blood vessel disease and Vascular Surgery
By Dr. Shafiq Qaadri, MD
What types of clinical problems does a vascular surgeon deal with?
There are several: basically you can think of the conditions as arterial, venous and lymphatic disorders outside of the heart.
Arterial disease includes aneurysms and arterial occlusive disorders. Aneurysms can occur in almost any blood vessel and can frequently present with rupture. The most common type is an abdominal aortic aneurysm (AAA) and the outcomes from elective surgery are far better than results from rupture.
Arterial occlusive disease, predominantly secondary to atherosclerosis, presents most commonly in the lower legs as claudication. This is called Peripheral Arterial Disease (PAD). In its most severe form, PAD presents as limb threatening ischemianight pain, rest pain, non-healing ulcers, or even gangrene.
Occlusive disease also affects the arch vessels, carotid arteries, renal and mesenteric vessels. We find ourselves frequently investigating and treating these sites also.
Venous disorders include varicose veins, venous ulcers, complications secondary to deep vein thrombosis and arteriovenous malformations. The vast majority of lymphatic disorders are treated non-operatively.
When should family physicians refer patients to a vascular surgeon?
Once preliminary investigations point toward vascular disease.
For example, for aneurysms this would include an abdominal ultrasound, for PAD an ankle brachial index (ABI). We prefer that ABI be performed in a vascular lab or radiology lab. For a swollen limb, a duplex ultrasound is done to rule out a deep vein thrombosis (DVT).
How can family doctors help reduce what seems to be the increasing burden of peripheral arterial disease?
Clinical PAD is an indicator of advanced atherosclerosis. It needs to be recognized as a significant risk factor for cardiovascular death. Family doctors need to treat those patients just as if they had a recent MI or stroke. Its that urgent.
Identification and treatment of risk factors such as smoking, hypertension, diabetes, and hyperlipidemia are all critical. Also, it is important not to overlook the benefits of physical fitness, proper weight control and a healthy balanced diet.
Should we screen patients for abdominal aortic aneurysms?
There is now excellent evidence for screening men and women for abdominal aortic aneurysms over the age of 50, if they have a family history of aneurysm.
Otherwise, all men between the ages of 60 and 80 should be screened. Only women over 60 who have cardiovascular risk factors should be screened, as they have a much lower incidence of aneurysms.
Do patients with claudication have a high risk of suffering a cardiovascular event?
Yes. The HOPE study had different subsets of PAD patients, those without clinical PAD and a normal ABI, those with two different levels of reduced (ABI) and those with clinical PAD.
The incidence of MI, CVA or cardiovascular death was highest in those with clinical PADabout 23 percent after 4? years of follow-up. This was compared to those without symptoms and a normal ABI>0.9in this group, only 14 percent had major events at the end of the 4? year follow-up.
Those with reduced ABIs had intermediate risk. What this tells us is that clinical PAD is a marker of significant cardiovascular risk.
Should family doctors routinely prescribe ACE inhibitors, ASA and statins for patients with claudication and peripheral arterial disease, even if they have no evidence of coronary artery disease?
The evidence for ASA is clear.
There is also evidence from HOPE and other trials that ACE inhibitors reduce the incidence of non-fatal myocardial infarction, non-fatal stroke and cardiovascular death in patients who are older than 55 and have a history of CAD, stroke, PAD or diabetes, and one other cardiovascular risk factor.
The benefit of ACE inhibitors was greater in the PAD population compared to the overall group in the trial. The mean blood pressure drop in the ACE treated group was only 2 to 4 mm Hg, but the benefits are far greater than you would think with such a minimal drop in BP.
There is no large trial that has been published that looks solely at PAD patients and statins. The Heart Protection Study enrolled patients with CAD, PAD or diabetes and a non-fasting total cholesterol of 3.5 mmol/L or greater. They were randomized to statin or placebo. Deaths for CAD, any vascular death or any vascular event were all significantly reduced.
So we recommend that patients with PAD should have a fasting LDL cholesterol of less than 2.5 mmol/L. More recent trials in CAD are showing further benefits of even lower cholesterol levels; however, their applicability to PAD patients is unknown.
What is the SAVR program at the Toronto General Hospital?
SAVR stands for Systematic Assessment of Vascular Risk. This program started within the division of vascular surgery to study the current state of risk factor management in our vascular patient population. We began this program to provide recommendations to primary care physicians regarding best practices.
Over 100 patients have been enrolled and early analysis has identified a significant care gap in risk factor management. A significant percentage of patients were not on anti-platelet therapy, many hypertensive patients still had elevated blood pressure even on therapy, elevated cholesterol was common even among those on treatment, new diabetics were uncovered, and 65 percent of patients were obese, with a BMI greater than 25.
Physician education is mandatory to disseminate the message that PAD means systemic atherosclerosis and high risk for vascular events and death. We hope that this will lead to increased use of proven risk-reduction therapies.
We have also studied the perceptions, knowledge and attitudes of Canadian vascular surgeons towards risk reduction. This assessment has revealed significant gaps, despite the fact that recommending and instituting therapy should be the responsibility of the vascular surgeon.
Given the heightened risk of cardiovascular disease in patients with PAD, these data have important and immediate implications.
What is the role of non-invasive repair of abdominal aortic aneurysms?
Endovascular AAA repair (EVAR) is a minimally invasive method to treat patients with aneurysms. This is accepted therapy around the world.
Two recent randomized trials have been published that demonstrate that EVAR leads to a reduction in 30-day mortality from 4.7 percent for open surgery, compared to 1.7 percent for EVAR.
To undergo EVAR, patients need to be evaluated by detailed imaging studies, usually fine-cut contrast CT, to determine if they meet the published anatomic criteria that are associated with high rates of success.
The rates of combined death or severe complications were also less in the EVAR groups. The EVAR group, however, requires more secondary interventions. Patients need to understand that life long follow-up with imagingCT scans or ultrasound with contrast agentsis required to ensure that aneurysms remain stable or shrink and no leaks develop.
In Ontario, EVAR has been used mostly in patients identified by vascular surgeons as having appropriate anatomy and higher than average risk for open repair. Funding for device costs for this new procedure has been haphazard, although a small prospective pilot study in Ontario has been recently completed.
I believe that this procedure, which requires specialized training and expertise, should be considered for those who are at high risk for conventional repair of aneurysm and have appropriate anatomy.
Should patients with asymptomatic carotid artery disease be referred to surgery?
Yes, and they can now be offered stenting.
A recent randomized prospective trial published this year demonstrated that conventional carotid endartectomy in asymptomatic men and women under the age of 75, with an ultrasound measured stenosis of 60 percent or greater, had a net 5-year stroke risk of 6 percent at 5 years. This is compared to 12 percent risk for those who did not undergo surgical management.
Despite the 3.1 percent incidence of perioperative stroke, after two years the number of events in the non-operative group became greater than the surgical group. The use of anti-platelet agents, anti-hypertensive agents and lipid lowering agents was similar in both groups at the outset and during follow-up. This suggests that, while medical management of cerebrovascular disease may have become more aggressive over the course of the trial, there was no evidence that it altered the results.
The role of carotid angioplasty and stenting (CAS) is more controversial. CAS techniques have improved because of advances in the FDA-approved cerebral protection devices. Randomized trials are now underway to compare surgery to CAS.
Currently, it is my impression that CAS is being practiced in selected centers in Canadaon patients who are perceived to be at high risk for carotid surgery, those with recurrent lesions, and those with lesions that are anatomically inaccessible to conventional surgery.
How can family doctors improve their understanding of PAD, and its associated risks?
There are many websites that offer information concerning PAD. The vascular web is an extensive site sponsored by the Society for Vascular Surgery, www.vascularweb.org. It contains information for patients as well as for physicians. It provides links to vascular journals, research, lists of ongoing clinical trials, and education. The American Heart Association has begun to devote web space to PAD, stroke and aneurysms, www.americanheart.org.
The current management of PAD and other vascular conditions is frequently highlighted at many CME events.
There is a statement from the Canadian Society for Vascular Surgery on EVAR. The Canadian Cardiovascular Society has a consensus statement on PAD, its risks and evidence-based treatment guidelines.
Dr. Shafiq Qaadri is a Toronto family physician and Continuing Medical Education lecturer. www.doctorQ.ca