P6172Management of silent myocardial ischemia in patients with peripheral arterial disease needing surgery

Background

Patients with peripheral arterial disease (PAD) needing surgery have increased risk for post-operative myocardial infarction (MI)/death due to coexisting coronary artery disease (CAD). Coronary CT angiography (CTA)-derived fractional flow reserve (FFRCT) can reliably identify ischemia-producing coronary stenosis in patients with suspected CAD but its value in PAD patients is unknown.

Purpose

To determine the prevalence of silent coronary ischemia in PAD patients undergoing surgery and to assess the value of FFRCT in guiding management of patients with multisite arterial ischemia.

Methods

Patients admitted for elective carotid, aortic or peripheral vascular surgery with no cardiac history or CAD symptoms were enrolled in a prospective, open-label, ethics committee-approved study and underwent pre-op CTA and FFRCT evaluation with results available to treating physicians. Ischemia-producing coronary stenosis was defined as FFRCT≤0.80 distal to stenosis in >2mm diameter vessels. Patient management was guided by a multidisciplinary team of cardiologists, cardiovascular surgeons and anaesthesiologists. Primary endpoint was major adverse cardiac events (MACE= cardiac death, MI, urgent revasc) at 30 days with follow up at 3,6,12 months.

Results

Coronary CTA and FFRCT analysis was performed in 179 consecutive patients (age 66±8 years, male 78%, hypertension 79%, diabetes 10%, dyslipidemia 31%, smoking 37%). CTA revealed extensive coronary calcification (Agatston score 995±1004, range 0–4810) and ≥50% stenosis in 64% of patients. Ischemic coronary stenosis (FFRCT≤0.80) was present in 114 patients (64%) with FFRCT ≤0.75 in 97 (54%) and multivessel ischemia in 63 (35%). Clinically indicated vascular surgery was performed as planned in 170/179 patients (95%) with cardiac anaesthesia and close monitoring and postponed in 9 patients for coronary revascularization (3) or medical/other therapy (6). There were no post-op cardiac complications. Elective coronary angiography, performed 1–3 months post surgery in 86 patients with left main, severe or multivessel ischemia, confirmed significant stenosis in each patient with revascularization in 58 patients (53 PCI and 5 CABG) including 8 for LM disease. There have been no cardiovascular deaths; 3 patients have died of lung cancer which was first discovered on CTA. One patient had peri-procedural MI at time of PCI and one had MI and urgent PCI at 6 months. MACE at 30 days=0/179, 3 months = 1/154, 6 months=2/123, 12 months=0/65.

Conclusions

Patients undergoing elective PAD surgery have a high prevalence (64%) of unsuspected ischemia-producing coronary stenosis. Pre-op diagnosis with CTA- FFRCT can help guide a multidisciplinary team approach with optimum medical management and staged peripheral and coronary revascularization. Favourable early results are promising and suggest the need for prospective controlled studies to define the role of coronary revascularization in PAD patients.

Acknowledgement/Funding

Heartflow, Inc.; Mikrotikls Ltd

Plasma HDL-cholesterol has an effect on nitric oxide production and arachidonic acid metabolism in the platelet membranes of coronary heart disease patients without LDL-hypercholesterolemia

AIM

To evaluate nitric oxide (NO) production and [3H]arachidonic acid (AA) incorporation into platelet membranes of coronary artery disease (CAD) patients with/without HDL-hypocholesterolemia.

MATERIAL

16 healthy controls (C), 14 CAD patients with plasma HDL-hypocholesterolemia (nCAD) and 14--without HDL-hypocholesterolemia (nCAD). All subjects were without peripheral vascular disease and hypertension. The groups were matched for age, sex, BMI. The diagnosis of CAD was substantiated by coronary angiography.

METHODS

Nitric oxide end products xNO (NO2- plus NO3-) levels in the platelet membranes were measured using anion-exchange chromatography. [3H]AA release from labelled platelets was studied by the method of Neufeld and Majerus; radioactivity was measured by liquid scintillation counting. Levels of plasma HDL-cholesterol (HDL-Ch) and triglycerides were enzymatically determined.

RESULTS

Significant increase (mean +/- SD; Mann-Whitney U test) of [3H]AA incorporation into platelet membrane phospholipids was noted in CAD patients in comparison with healthy subjects (p < 0.001). A correlation (multiple regression analysis) was established between HDL-C level and [3H]AA (r = -0.58, p < 0.05, n = 28); and between HDL-Ch and NOx levels (r = 0.76, p < 0.05, n = 28) in CAD patients. CAD patients had lower NOx than healthy subjects (p < 0.0001), NOx was lower in the group with decreased HDL-Ch concentration (wCAD 36 +/- 5 vs. nCAD 42.3 +/- 6 mumol/mg, p < 0.002).

CONCLUSIONS

CAD patients show decreased ability to produce platelet-derived NO that leads to higher platelet sensitivity to aggregating stimuli. Decreased plasma HDL-Ch may affect AA metabolism and NO production in the platelet membranes of CAD patients without LDL-hypercholesterolemia.