Michael H. Sketch

Percutaneous revascularization of chronic coronary occlusions: An overview

Patients with a chronic coronary occlusion often undergo coronary angiography after weeks to months of occlusion. The published reports underestimate the extent of this problem because such patients are often arbitrarily assigned to receive medical therapy or undergo bypass surgery as a result of poor success with percutaneous revascularization and substantial restenosis. Thus, there is controversy about the role of angioplasty in this patient cohort. The goal of this overview was to evaluate the available information about angioplasty in chronic coronary occlusions. The primary indication for attempted recanalization of a chronic coronary occlusion has been symptomatic angina pectoris. Anginal status often improves after successful procedures (70% vs. 31% with a failed procedure); left ventricular function may improve; and subsequent referral for coronary artery bypass graft surgery is uncommon (3% vs. 28% in unsuccessful cases). Successful recanalization is achieved in approximately 65% of attempted procedures. Inability to cross the stenosis with a guide wire is the most common cause of procedural failure. Statistically significant predictors of procedural success include older occlusions (75% < 3 months old vs. 37% > or = 3 months old), absence of any anterograde flow through the occlusion (76% with vs. 58% without), angiographically abrupt-appearing occlusions (50% vs. 77% with tapered occlusions), presence of bridging collateral vessels (23% with vs. 71% without) and lesions > 15 mm. Procedural complications occur at a slightly lower incidence than in angioplasty of high grade subtotal stenoses. Long-term success is limited, and restenosis can be expected in > 50% of the patients. The experience with chronic total occlusions of saphenous vein bypass grafts is small, but there appear to be limited procedural success and significant procedural complications, particularly associated with distal emboli. The role of new pharmacologic agents has yet to be defined and that of new devices has been disappointing so far, but further technologic advances are on the horizon.

Impact of Recovery of Renal Function on Long-Term Mortality After Coronary Artery Bypass Grafting

Whether prognosis differs in acute renal failure (ARF) after coronary artery bypass grafting (CABG) in patients with and without recovery of renal function is not known. We studied patients who had CABG at Duke University Medical Center (1995 to 2008). ARF was defined as an increase in peak creatinine ≥50% after CABG or ≥0.7 mg/dl above baseline or need for new dialysis. Patients were categorized into 3 groups: (1) no ARF after CABG, (2) ARF after CABG and completely recovered renal function at day 7 (return of creatinine to no higher than baseline and no dialysis), or (3) ARF after CABG with no recovery of renal function at day 7 (creatinine no higher than baseline or new dialysis). Main outcome measurement was risk-adjusted long-term mortality (excluding death ≤7 days). ARF after CABG occurred in 2,083 of 10,415 patients (20%) and completely recovered in 703 (33.7%). Risk-adjusted mortality was highest in patients with ARF without recovery of renal function (hazard ratios 1.47, 95% confidence interval 1.34 to 1.62) and intermediate in those with ARF but completely recovered renal function (hazard ratios 1.21, 95% confidence interval 1.07 to 1.37, referent no-ARF group). Mortality was lower in patients with ARF compared to those without complete recovery of renal function (p = 0.0083). In conclusion, in patients with ARF after CABG, complete recovery of renal function was associated with significantly lower long-term mortality compared to those without such recovery, although this was significantly higher than in those without ARF. Thus, major emphasis should be on prevention of ARF in patients undergoing CABG.

Provisional stenting strategies: systematic overview and implications for clinical decision-making ☆

Coronary stents reduce the rates of abrupt closure, emergency coronary artery bypass graft surgery and restenosis, but do not prevent myocardial infarction or death at six months. The financial burden of increased stent use and the difficulty in managing in-stent restenosis have provided the impetus to develop provisional stenting strategies. Patients at low risk for restenosis after balloon angioplasty may not derive additional benefit from stent implantation and may be successfully managed with percutaneous transluminal coronary angioplasty (PTCA) alone. Numerous patient, lesion and procedural predictors of restenosis have been identified. Postprocedural assessment using quantitative coronary angiography, intravascular ultrasound (IVUS), coronary flow velocity reserve (CVR) or fractional flow reserve (FFR) may further enhance the ability to predict adverse outcomes after PTCA. Several studies have been performed to investigate the feasibility of provisional stenting strategies using various modalities to identify low risk patients who could be managed with PTCA alone. An optimal or stent-like angiographic result after PTCA is associated with favorable clinical outcomes. Preliminary results of studies using IVUS or CVR to guide provisional stenting appear promising. Angiography alone may be inadequate to identify truly low risk patients and may need to be combined with clinical factors, assessment of recoil, IVUS or physiologic indexes. Strategies that avoid unnecessary stenting in even a small proportion of patients may have large impacts on health care costs. Provisional stenting may potentially reduce costs and rates of in-stent restenosis without compromising the quality of health care delivery.

Prospective analysis of possible myocardial damage or hemolysis occurring as a result of prolonged autoperfusion angioplasty in humans

OBJECTIVESnThe purpose of this study was to further explore the procedural safety of prolonged (15-min) dilation using an autoperfusion coronary angioplasty balloon by assessing the degree of myocardial damage or hemolysis, if any, occurring as a result of the procedure.nnnBACKGROUNDnProlonged balloon inflation periods may be beneficial during percutaneous transluminal coronary angioplasty. The duration of standard balloon angioplasty is often limited by the occurrence of myocardial ischemia due to loss of anterograde blood flow. Autoperfusion angioplasty allows continued myocardial perfusion during balloon inflation and has previously been shown to reduce but not totally eliminate acute myocardial ischemia during prolonged (up to 15 min) balloon inflation. The risk of intravascular hemolysis as a result of autoperfusion angioplasty has not yet been fully delineated.nnnMETHODSnSixty-two consecutive patients (76% men; mean age 58 years) undergoing elective percutaneous transluminal coronary angioplasty of a single lesion were studied. Serial electrocardiographic and creatine kinase MB isoenzyme data were examined to detect evidence of myocardial damage. Tests for hemolysis (plasma free hemoglobin, serum haptoglobin and serum lactate dehydrogenase) were obtained in the 1st 24 consecutive patients.nnnRESULTSnInflation time was 14 +/- 4 min (mean +/- SD) and the procedure was successful (less than or equal to 50% residual lesion stenosis) in 59 patients (95%). Electrocardiographic evidence of myocardial infarction (greater than 1 mm persistent ST segment depression, greater than 1 mm ST segment elevation or new Q waves) was not observed in any patient. Cardiac enzyme assays were within the normal range in all patients. No evidence of hemolysis was found in the 24 consecutive patients studied.nnnCONCLUSIONSnWe conclude that prolonged autoperfusion angioplasty can be performed in patients without clinical evidence of myocardial damage or hemolysis.

710-5 Progressive Deterioration in Late (2-Year) Clinical Outcomes After Stent Implantation in Saphenous Vein Grafts: The Multicenter JJIS Experience

Late clinical follow-up (after I-year) in patients treated with native coronary stents demonstrates no further clinical events (death or MI) and rare delayed target lesion revascularization (TLRxa0=xa0repeat PTCA or CABG). To examine the long-term effects of stent placement in saphenous vein grafts (SVG), we evaluated all follow-up clinical data in 661 consecutive patients (775 SVG lesions) from the JJIS multicenter registry (17 sites). Baseline demographics were pertinent for a high incidence of unstable angina (72%), heart failure (22%), and high surgical risk status (49%). The mean SVG age was 9xa0±xa04 years, and the mean ejection fraction was 49xa0±xa014%. Overall procedure success (l50% residual stenosis without in-hospital death. MI, or CABG) was 92%, and subacute thrombosis was documented in 9 patients (14%). Actuarial follow-up event rates: Events 6-months 12-months 24-months – Death (%) 5 8 14 – MI(%) 7 8 8 – CABG (%) 7 9 12 – PTCA(%) 6 8 12 – Event-free survival (%) 75 67 55 Event-free survival = freedom from death, MI. CABG or PTCA Conclusion Similar to PTCA in SVG lesions and in contrast to stents in native coronaries, patients with stents in SVGs exhibit a disappointing attrition in late clinical outcomes beyond one year, Both increasing mortality and repeat revascularization procedures contribute to the 2-year 55% event-free survival. We surmise that further deterioration at the stent site (i.e. “late” restenosis), increasing non-TLR events, and less favorable baseline characteristics are responsible for these findings.

738–2 The Evolution of Therapy for Single Vessel Disease: A Treatment Comparison of Medicine, Angioplasty and Left Internal Mammary Artery Graft for Proximal Left Anterior Descending Disease

Saphenous vein bypass grafting for single vessel disease offers no survival or symptom relief advantage compared to medical therapy. Recent evidence suggests the use of the internal mammary artery or PTCA may be more beneficial than medicine. To examine the outcome of these treatment strategies, a retrospective analysis of prospectively collected data on 23,018 consecutive patients undergoing cardiac catheterization between April 1986 and February 1994 was performed. Of the 6,432 patients with single vessel disease, 1,222 had a proximal left anterior descending (LAD) stenosisxa0gxa074% and no prior PTCA or CABG. A total of 289 were managed medically, 760 underwent PTCA, and 172 received a left internal mammary artery (LIMA) graft. Baseline demographic data and risk factor profiles were similar except for a higher incidence of diabetes (19 vs 15 vs 11%), history of MI (72 vs 58 vs 48%) CHF (18 vs 7 vs 8%), and total occlusions (44 vs 17 vs 7%) and lower incidence of unstable angina (40 vs 61 vs 64%) in the medical group as compared to PTCA and LIMA graft, respectively. Kaplan-Meier 6-year estimates: Events Medicine PTCA LIMA P-value xa0–xa0unadjusted survival (%) 78 85 91 0.001 xa0–xa0adjusted survival (%) 84 86 90 0.24 xa0–xa0event-free survival (%) 54 43 72 0.0001 Conclusion There is a trend towards improved long-term survival in proximal LAD disease with a strategy of revascularization, particularly the LIMA graft. Furthermore, event-free survival is significantly improved with the LIMA graft as compared to medical therapy or PTCA.

Noncardiac Surgery: Evaluating and Minimizing Cardiac Risk

Perioperative cardiac complications remain a great concern during noncardiac surgeries since a large majority of patients undergoing such procedures are elderly, who have a greater prevalence of coronary artery disease. Thus, it is imperative to assess risk of perioperative cardiac complications in all patients scheduled for noncardiac surgery. The current review attempts to outline a systematic approach to assess cardiac risk for noncardiac surgery and suggest strategies to minimize these risks. This approach uses a combination of the urgency of noncardiac surgery, interval since prior revascularization to noncardiac surgery, the interval between prior evaluation of coronary artery disease, patients clinical risks for cardiac complications, and patients functional status to decide their perioperative cardiac risks. If surgery is urgent or the estimated risk for perioperative event is low, then irrespective of the risk, patients should proceed with noncardiac surgery under the influence of appropriate medical strategy to minimize risk. If patients risk of perioperative events is high, then postponing or canceling surgery and referral for invasive approach to identify and when appropriate revascularize coronary artery disease may help reduce the perioperative cardiac risk. In contrast, patients at intermediate risk for perioperative events may benefit from noninvasive assessment for coronary artery disease and referral for appropriate patients for coronary revascularization based on the results of such noninvasive testing. Medical perioperative strategy that should be part of all patients undergoing noncardiac surgery who have or are at risk for coronary artery disease, should include betablockers, adequate analgesia, monitoring fluid status, and maintaining hematocrit > 30 gm /dl. Finally, the physician-patient interaction during the hospitalization during noncardiac surgery should be recognized as an important opportunity to institute secondary prevention strategies for coronary artery disease in patients at risk for coronary atherosclerosis.

738–3 Long-term Survival with a Chronic Total Coronary Occlusion: A Comparison of Medical Therapy versus Angloplasty in Patients with Single Vessel Disease

While medical management of pts with single vessel chronic total occlusions has been associated with high rates of death, MI and need for revascularization at long-term follow-up, the role of PTCA in these pts is poorly defined. To develop a paradigm for the comparison of medical therapy versus PTCA in the management of chronic total occlusions, we retrospectively analyzed prospectively-collected data on 23,005 pts undergoing cardiac catherization between April 1986 and February 1994. Of the 6,430 pts with single-vessel disease, 748 had a total occlusion without an acute myocardial infarction within 30 days and no history of PTCA or CABG. A total of 611 pts were managed medically and 137 pts underwent PTCA. The 2 groups were similar with regard to most baseline characteristics, but the medically-treated group had higher rates of CHF (16 vs 9%) and prior MI (50 vs 31%), and the PTCA cohort had more unstable angina (36 vs 20%) and left anterior decending disease (63 vs 34%). While early mortality was similar, the 4-year mortality was statistically insignificantly higher in the medical cohort (12 vs 7%). Kaplan-Meier 4-year estimates: Events Medicine (%) PTCA(%) P-value xa0–xa0CABG 10 30 0.0001 xa0–xa0PTCA 8 33 0.0001 xa0–xa0MI 6 10 0.009 Conclusion The trend towards lower mortality in the presence of higher non-fatal events provides a rationale for opening chronic total occlusions that can be tested in larger prospective studies.

731-2 Angiographic and Clinical Follow-up After Internal Mammary Artery Graft Angioplasty: A 9-Year Experience

Acute and long-term efficacy of internal mammary artery (IMA) graft angioplasty has been limited to isolated ease reports and small patient series with limited angiographic follow-up. Over a 9-year period, 68 consecutive patients (74% male; median age: 61 yrs) underwent PTCA of IMA stenoses. In 59 patients, the lesion was located at the distal anastomosis, while in 9 patients, the lesion was located in the body of the graft. Median graft age was 9 months. The procedural success rate was 88%. The unsuccessful procedures were due to: inability to cross with wire/device due to excessive vessel tortuosity (5), major dissection (2), and inability to dilate (1). No patient experienced an in-hospital re-occlusion, distal embolization or CABG. Angiographic follow-up was obtained in 78% of successful procedures at a mean interval of 8 months. Restenosis (g50% luminal diameter narrowing) occurred in 9 patients (19%). A sub-analysis by lesion site revealed a restenosis rate of 15% (6/40) at the distal anastomosis and 43% (3/7) in the body of the graft. At a mean clinical follow-up of 14 months, 76% of patients had Class I or II angina, and event-free survival was 86%. Conclusion Angioplasty of IMA grafts is associated with excellent acute and long-term outcome. The restenosis rate of IMA anastomotic lesions appears to be lower than either native arteries or saphenous vein grafts.

Quantitative coronary angiography after revascularization with the transluminal extraction-endarterectomy catheter (TECTM)

Despite a seemingly exponential rise in the number of coronary angioplasty procedures since the introduction of the procedure in 1977, several major limitations to more widespread use still remain. These include difficulty traversing chronic total occlusions, the development of major dissection with an attendant increase in the risk of abrupt closure and the continuing problem of restenosis in a significant minority of patients. This has resulted in the development of a number of new technologies to address some facet of each of the above limitations. One promising new device is the Transluminal Extraction-endarterectomy Catheter (TEC). The device is introduced percutaneously and consists of a flexible torque tube that tracks over a flexible guidewire under standard fluoroscopic guidance. A unique feature of the TEC is the simultaneous application of suction while the conical cutter rotates and removes atheromatous plaque. This reservoir allows for the collection of the excised fragments for later analysis.