Frank A. Schmieder

Managing PAD with multiple platelet inhibitors: the effect of combination therapy on bleeding time

PURPOSE Patients with lower-extremity peripheral arterial disease (PAD) face a high risk of cardiovascular morbidity and mortality. Platelet inhibition (PI) significantly reduces this risk. Combination PI is common and increasingly indicated in patients with PAD; however, the effect on platelet function has not been objectively evaluated. Aspirin (ASA), clopidogrel (Clop), and cilostazol (Cilo) are the three most commonly used PI drugs in patients with PAD. A prospective, sequential evaluation of platelet function using the template bleeding time (BT) was performed for PAD patients taking these medications singly and in combination. METHODS Twenty-one patients with PAD, averaging 65.9 years of age, were studied. Patients were placed on sequential two-week regimens of the following therapies: washout (no PI), ASA (325 mg daily), ASA + Cilo (100 mg twice daily), washout, Cilo, Cilo + Clop (75 mg each day), washout, Clop, Clop + ASA, and Clop + ASA + Cilo. At the end of each phase, trained personnel measured the BT. RESULTS Baseline bleeding time for the group was 4.29 +/- 1.69 minutes. ASA (BT = 6.64 +/- 3.52) and Clop (BT = 10.17 +/- 5.4) significantly prolonged bleeding time (P < 0.01); however, no significant effect was observed with Cilo alone (BT = 5.41 +/- 2.69). Combined treatment with ASA + Clop (BT = 17.39 +/- 4.59) had a more pronounced effect on BT compared with either agent alone (P < 0.01). The addition of Cilo to either ASA (BT = 8.3 +/- 4.27) or Clop (BT = 12.7 +/- 7.46) or the combination of ASA + Clop (BT = 17.92 +/- 4.69) did not prolong BT. CONCLUSION All patients with PAD require platelet inhibition, and many require pharmacotherapy for intermittent claudication. The platelet inhibitors aspirin and clopidogrel are used for the reduction of ischemic events. They significantly prolong bleeding time individually and to a greater extent in combination. Cilo is used to improve walking distance in patients with intermittent claudication. When Cilo is added to ASA, Clop, or the combination of the two, there is no additional increase in bleeding time. Therefore, Cilo can be used in combination with other platelet inhibitors without an additional effect on platelet function as reflected by the bleeding time.

Intermittent claudication: magnitude of the problem, patient evaluation, and therapeutic strategies.

Intermittent claudication (IC), the symptom of exercise-induced muscle ischemia of peripheral arterial disease (PAD), afflicts and limits the activities of a significant number of patients. Incidence and prevalence of IC depends on the population studied and the diagnostic instruments used. In large studies, prevalence has ranged from 3% to 10%, with a sharp increase in those aged > or =70 years. Over the next 20 years, the total number of patients affected is expected to increase significantly due to anticipated demographic changes. Analysis of the natural history of IC demonstrates that the risk of cardiovascular morbidity and mortality far exceeds that of severe limb ischemia or limb loss. In fact, only 2% to 4% of all patients with IC will require a major amputation in their lifetime. However, life expectancy is approximately 10 years less than that of an age-matched cohort. By now, PAD is well recognized as a marker of systemic atherosclerosis. The cornerstone of patient evaluation is a history and physical examination, including a detailed atherosclerotic risk-factor assessment. In the differential diagnosis of IC, clinicians should consider etiologies such as arthritis, spinal stenosis, radiculopathy, venous claudication, or inflammatory processes. In >80% of all patients, it is possible to locate the responsible arterial segment by combining the location and severity of pain with a pulse examination. Noninvasive diagnostic studies help determine the level of disease, may unmask a hemodynamically significant stenosis, and are useful in follow-up. Arteriography is reserved for patients in whom the decision for revascularization has been made. Knowing the anatomic detail of a lesion allows the clinician to determine whether and what type of intervention is feasible. Standard therapy for all patients should be directed at both peripheral and systemic atherosclerosis, beginning with risk-factor modification in the form of smoking cessation, optimal diabetes control, and lipid normalization. The benefits of supervised exercise rehabilitation include significantly increased walking distance and enhanced quality of life. Platelet inhibition has been shown to reduce the risk of ischemic stroke, myocardial infarction, and vascular death and should be prescribed for all but those in whom it is medically contraindicated. Symptom-specific pharmacotherapy with a broad range of medications has yielded disappointing results in the past. However, recent studies have demonstrated that patients receiving the novel agent cilostazol experienced increases in walking distance and improvements in quality of life.

Temporary femoral artery bifurcation shunting following penetrating trauma

Penetrating common femoral artery injuries are life-threatening, especially when the femoral bifurcation has been destroyed. In the presence of other associated injuries which preclude immediate definitive vascular reconstruction, temporary arterial shunting may be useful. Presently available shunts, however, are tubular and allow for distal perfusion to only one vessel. We have utilized a modified bifurcated hemodialysis catheter (Mahurkar MAXID; Tyco Healthcare, Mansfield, Mass) to successfully provide simultaneous perfusion from the proximal common femoral artery to both the superficial and deep femoral vessels. Such catheters are readily available in most institutions, can be quickly modified, and are easy use in urgent trauma situations.

Long-Term Outcomes of Fistula First Initiative in an Urban University Hospital—Is It Still Relevant?

Purpose: Dialysis access failure is a major cause of morbidity in patients with end-stage renal disease. The Fistula First Breakthrough Initiative (FFBI) dictates arteriovenous fistulae (AVFs) should be preferred over arteriovenous grafts (AVGs) as first line for surgically placed accesses. The purpose of this study was to compare patency rates of surgical dialysis accesses in our mature, urban population after the FFBI. Methods: Current dialysis patients with accesses placed between 2006 and 2011 were included. Patient characteristics, access outcomes, interventions, and survival outcomes were analyzed. Results: We report outcomes of 220 patients undergoing dialysis access. Of those 220, 75 received numerous accesses. All outcomes are evaluated as per access itself, that is, a patient may have numerous access types, each individually analyzed. Of the accesses, 138 were AVF and 190 were AVG. The average age of patients was 59.8 years. The groups were evenly matched in distribution of race and prevalence of hypertension, diabetes, coronary artery disease, and Peripheral Vascular Disease (PVD). Average number of complications requiring intervention per access were fewer with AVF than AVG (1.21 vs 1.72, P = .02). The AVF had greater rates of stenosis (51.4% vs 40.6%, P = .0182), whereas AVG had greater thrombosis rates (14.6% vs 31.9%, P < .001). Both AVF and AVG had similar primary patency (median: 186 vs 142 days, P = .1774) and 3-year secondary patency (59.2% vs 49.2%, P = .0945). Arteriovenous fistula in patients aged <60 years was found to have the greatest primary (P = .0078) and secondary patency (P = .0400). Outcomes did not differ between AVF and AVG in those aged >60 years. Conclusions: Although complications requiring intervention are greater with AVG, primary and secondary patency rates are similar between AVF and AVG, except when considering AVF in patients aged <60 years.

The impact of chronic kidney disease on lower extremity bypass outcomes in patients with critical limb ischemia

Objective Patient selection for open lower extremity revascularization in patients with chronic kidney disease (CKD) remains a clinical challenge. This study investigates the impact of CKD on early graft failure, postoperative complications, and mortality in patients undergoing lower extremity bypass for critical limb ischemia. Methods The National Surgical Quality Improvement Program database was queried for all patients with critical limb ischemia from 2012 to 2015 who underwent lower extremity bypass using the targeted vascular set. The glomerular filtration rate was calculated using the Chronic Kidney Disease Epidemiology Collaboration Study equation. CKD categories were determined from the National Kidney Foundation Kidney Disease Outcomes Quality Initiative staging criteria. Patients were classified into three groups: CKD stages 3 or lower (mild to moderate CKD), CKD stages 4 or 5 (severe CKD), and on hemodialysis (HD). Multiple variable analysis was used to examine graft failure, mortality, and postoperative complications. Results The Surgical Quality Improvement Program database identified 6978 patients who underwent infrainguinal lower extremity arterial bypass during the study period. There were 6101 patients (87.4%) with mild to moderate CKD, 327 (4.7%) with severe CKD, and 550 (7.9%) on HD. Patients with severe CKD and on HD were more likely to have revascularization for tissue loss (54.9% vs 68.8% and 74.7%; P < .01). Patients with severe CKD and those on HD had higher rates of early graft failure, postoperative myocardial infarction, and rates of reoperation. Multiple variable analysis confirmed these results showing that HD was associated with postoperative myocardial infarction, readmission, and increased mortality. It also demonstrated that severe CKD was associated with graft failure (odds ratio [OR], 1.67; 95% confidence interval [CI], 1.12‐2.50; P = .01), postoperative myocardial infarction (OR, 2.16; 95% CI, 1.35‐3.45; P < .01), and readmission (OR, 1.38; 95% CI, 1.06‐1.80; P = .02). Other factors associated with graft failure include functional status (OR, 1.39; 95% CI, 1.08‐1.80; P = .01), African American race (OR, 1.72; 95% CI, 1.39‐2.13; P < .01), and distal bypass (OR, 1.33; 95% CI, 1.09‐1.61; P < .01). Conclusions CKD is a significant predictor of perioperative morbidity after lower extremity bypass. Patients with severe CKD have worse postoperative outcomes without increased mortality. Those on HD have worse survival and postoperative outcomes.

PC162. Outcomes of Below-Knee Amputation for Lower Extremity Infection: One-Stage versus Two-Stage Operative Approach

6 3.5. The risk score was divided into low-risk [0-4 points, n 1⁄4 5,272 (52%); NHD 1⁄4 10.1%] moderate-risk [5-9 points, n 1⁄4 3663 (36.7%) NHD 1⁄4 36.7%], and high-risk [10 points, n 1⁄4 1210 (11.9%) NHD 1⁄4 66.1%). Conclusions: A novel risk score was highly predictive for NHD after bypass for LEI using only preoperative comorbidities. High-risk patients account for 12% of bypasses but nearly a third of all patients with NHD. This risk score can be used to determine high-risk patients for discharge preoperatively allowing providers to anticipate their need in the preoperative setting or upon immediate presentation to the hospital.

IP205. Outcomes After Open Lower Extremity Revascularization in Patients With Chronic Kidney Disease

(range, 1-79 months) with a primary patency of 85.4%. Cumulative primary assisted and secondary patency was 92.6%. The femoral patch repair was the most frequent site of reintervention. Mortality was 34% overall during the study period with one death at 30 days. Conclusions:Hybrid approach has lowmorbidity andmortality and fast recovery. It is a safe, effective and lasting treatment for TASC C and D aortoiliac occlusive disease involving the femoral bifurcation. The use of covered stents provides good midterm patency. Close follow-up with noninvasive imaging is paramount to avoiding repair failure by diagnosing recurrent stenosis, in particular at the femoral patch repair site.

Chronic Critical Limb Ischemia

Chronic critical limb ischemia (CLI) represents the most advanced form of atherosclerotic lower extremity vascular disease. By definition, the term characterizes patients with distal extremity perfusion so limited as to produce rest pain and/or tissue necrosis in the form of ischemic ulcers and gangrene. Clinically, patients with CLI differ from those with intermittent claudication (IC) by symptoms of ischemia present at rest as well as evidence of tissue breakdown or loss due to hypoperfusion. Acute limb ischemia (ALI), on the other hand, describes the patient in whom blood supply is suddenly interrupted, leading to sensory-motor symptoms and potential tissue destruction in short order if perfusion is not restored (see Chapter 7). ALI may occur in conjunction with CLI when a vessel with high-grade stenosis undergoes thrombosis or an embolus is superimposed on preexisting disease.