812
Emergent Use of Balloon-Expandable Coronary Artery Stenting for Failed Percutaneous Transluminal Coronary Angioplasty Howard C. Herrmann, MD; Maurice Buchbinder, MD; Michael W. Clemen, MD; David Fischman, MD; Sheldon Goldberg, MD; Martin B. Leon, MD; Richard A. Schatz, MD; Paul Tierstein, MD; Craig M. Walker, MD; and John W. Hirshfeld Jr., MD Background. The balloon-expandable intracoronary stent developed by Palmaz and Schatz is undergoing clinical evaluation for use in unfavorable anatomic situations and in the prevention of restenosis. Because the stent's mechanism of action would suggest effectiveness in salvaging certain percutaneous transluminal coronary angioplasty (PTCA) failures, we retrospectively examined the results of emergency unplanned coronary artery stenting for failed PTCA procedures, including acute occlusion. Methods and Resus. The study population consisted of all US patients receiving emergency unplanned stent implantation in a nonrandomized fashion at seven centers over a 2½2-year period (n =56). All available medical records and angiograms were reviewed to determine retrospectively the reason for stenting: Group 1 consisted of 23 patients with a suboptimal angioplasty result; group 2 included patients with evidence of impending vessel closure after PTCA (n= 15); and group 3 were patients with frank acute occlusion after PTCA (n=18). The immediate and final (30-day) results of stenting were examined with respect to major complications, which included death, need for coronary artery bypass graft surgery, and occurrence of myocardial infarction. Finally, restenosis rates (>50o% stenosis) based on follow-up angiography were calculated. Baseline characteristics of the study population included a mean±SD age of 58±+11 years and a large prevalence of angiographic characteristics generally considered unfavorable for PTCA, which include lesion eccentricity (49o), intimal dissection (9%o), or angiographically visible thrombus (6%). After conventional balloon angioplasty, there was an increased incidence of intimal dissection (74%) and thrombus formation (38%1), and overall stenosis severity was unchanged (75±12% versus 70+27%, p=NS). Successful stent deployment was achieved in 55 (981%o) of 56 patients with initial success (freedom from death, surgery, and infarction) in 52 (93%) of 56 patients. The success rate at 1 month fell to 71% primarily because of the occurrence of subacute stent thrombosis (16%) and its associated complications. Overall, major complications occurred in 16 (29%) of 56 patients within 30 days. The only predictor of subacute stent thrombosis in multiple stepwise logistic regression analysis was the presence of angiographically visible thrombus after stenting (p=0.03). Angiographic restenosis was documented in eight (23%) of 35 eligible patients. Conclusions. Emergency stenting may be a useful and effective treatment for failed angioplasty. High initial success rates (>90%) can be achieved, but subsequent complications, often related to subacute thrombosis, occur in a substantial portion of patients. Patients who receive stents on an emergency basis, particularly those with previous acute occlusion, should be considered to be at greater than usual risk for complications and receive more careful anticoagulation and follow-up. (Circulation 1992;86:812-819) KEY WoRDs * restenosis * percutaneous transluminal coronary angioplasty * stents
T he immediate success rate of percutaneous transluminal coronary angioplasty (PTCA) generally exceeds 90%; however, failure to achieve an adequate result of .50% luminal diameter stenosis, All editorial decisions for this article, including selection of reviewers and the final decision, were made by a guest editor. This procedure applies to all manuscripts with authors from the University of California San Diego or UCSD Medical Center. From the Cardiovascular Division, Department of Medicine, Hospital of the University of Pennsylvania, University of Pennsylvania School of Medicine, Philadelphia, Pa. One of the authors (R.A.S.) is coinventor of the device described and holds an equity position with Johnson & Johnson. Address for reprints: Howard C. Herrmann, MD, 9 Founders Pavilion, Hospital of the University of Pennsylvania, 3400 Spruce Street, Philadelphia, PA 19104. Received March 9, 1992; revision accepted May 28, 1992.
caused by vasospasm, dissection, thrombus, and elastic recoil, may occur in as many as 10% of all procedures.1,2 Furthermore, acute occlusion occurs in 2-7% of all PTCA procedures and is associated with a high rate of complications, including death, myocardial infarction, and emergency coronary artery bypass graft surgery (CABG).1-6 Restenosis also may occur more frequently in patients with acute occlusion even after successful recanalization.7,8 The balloon-expandable intracoronary stent developed by Palmaz and Schatz recently has been introduced and is undergoing clinical evaluation for use in unfavorable anatomic situations and in the prevention of restenosis.9 The stent's mechanism of action would suggest that it might also be effective in salvaging certain PTCA failures by stabilizing dissections and opposing
Downloaded from http://circ.ahajournals.org/ at University of Pittsburgh--HSLS on March 16, 2015
Herrmann et al Emergent Balloon-Expandable Coronary Artery Stenting
elastic recoil and spasm. Several small and preliminary studies have reported on the use of the Palmaz-Schatz and other stents in emergency settings after failed PTCA.4 '0" In this cooperative effort from the US centers using the Palmaz-Schatz stent, we retrospectively analyzed the results, complications, and follow-up of nonprotocol, emergency, unplanned coronary stenting after PTCA, including failed procedures. Methods Study Population The study population consisted of all US patients receiving emergency unplanned implantation of one or more Palmaz-Schatz coronary artery stents at one of seven centers from November 1988 to July 1991. These patients were not participants in the usual stent protocols at the participating institutions and entered the laboratory with plans for conventional PTCA. Consent for emergency stenting was obtained in the catheterization laboratory just before stent implantation after consultation with the patient, their families and physicians, and a member of the institutional review board. Subsequently, a formal description of the indications and outcome of the procedure was forwarded to the institutional review board and the manufacturer. To further determine the reason for stenting in these nonprotocol patients, the medical record and angiograms were reviewed and subjects were retrospectively assigned to one of three groups: Group 1 consisted of patients receiving stents for a suboptimal angiographic angioplasty result considered unacceptable by the individual investigator; group 2 included patients with evidence for impending closure after PTCA, which was defined as a decrease of Thrombolysis in Myocardial Infarction trial (TIMI) flow grade .1 associated with clinical evidence of ischemia, which included chest pain and ECG changes; and group 3 were patients with acute occlusion after PTCA (TIMI flow grade 0 or 1 and .99% stenosis).
Definitions Immediate and final success were defined as successful stent deployment with establishment of TIMI grade 3 antegrade flow through the dilated segment and the absence of major complications during the procedure and within 30 days, respectively. Patients were considered to have unstable angina if they experienced symptoms at rest before the procedure. Stents were delivered hand-crimped on an angioplasty balloon before December 1990 (80%) and subsequently using a sheath delivery system. All patients received aspirin, dipyridamole, and dextran (10%) before stent deployment. Major complications included death, need for CABG, or the occurrence of Q and non-Q wave myocardial infarction. Restenosis stent
on a
was defined as .50% stenosis within the scheduled 6-month angiogram.
Angiographic Review All available angiograms (96%) were reviewed by two angiographers (H.C.H. and J.W.H.). Each film was analyzed for group assignment, baseline angiographic lesion characteristics including the presence of thrombus (filling defect with contrast agent on three sides), dissection (filling defect with extraluminal extravasation
TABLE 1. Baseline Characteristics Age (years) Sex (% male) Clinical history (n=51) Unstable angina Previous PTCA target lesion No. of stents placed Reason for stenting (n=56) Suboptimal result Impending closure Acute occlusion Vessel stented (n=56) LAD RCA LCx SVG Modified ACC/AHA class (n=56) A Bi B2 C
813
58+ 11 75 26 (51%) 16 (31%)
55/56 attempts 23 (41%) 15 (27%) 18 (32%) 24 (44%) 19 (35%) 7 (13%) 5 (9%) 10 (19%) 21 (40%) 17 (32%) 5 (9%)
PTCA, percutaneous transluminal coronary angioplasty; LAD, left anterior descending coronary artery; RCA, right coronary artery; LCx, left circumflex artery; SVG, saphenous vein graft; ACC, American College of Cardiology; AHA, American Heart Association.
of contrast agent), eccentricity, TIMI perfusion grade,12 modified American College of Cardiology-American Heart Association (ACC/AHA) score,13 and measured percentage stenosis. The same characteristics were also evaluated after the last balloon inflation before stent deployment and on the final angiogram after the stent was implanted. Quantitative coronary angiographic measurements (percent stenosis) were made using digital electronic calipers. Previous studies have shown such systems to have a high correlation with computerassisted methods with acceptably low intraobserver and interobserver variabilities.14'15
Statistics Results are expressed as mean±SD. Comparisons between groups were made by Scheffe's multiple comparison test, and subgroup comparisons were made by X2 analysis using standard formulas (STATVIEW statistical software, Calabresa, Calif.). Predictors of complications and restenosis were analyzed using multiple stepwise logistic regression of all demographic, procedural, and angiographic variables (spss statistical analysis software, Release 4 for the Macintosh, SPSS Inc., Chicago, Ill.). Results were considered significant if p
Emergent Use of Balloon-Expandable Coronary Artery Stenting for Failed Percutaneous Transluminal Coronary Angioplasty Howard C. Herrmann, MD; Maurice Buchbinder, MD; Michael W. Clemen, MD; David Fischman, MD; Sheldon Goldberg, MD; Martin B. Leon, MD; Richard A. Schatz, MD; Paul Tierstein, MD; Craig M. Walker, MD; and John W. Hirshfeld Jr., MD Background. The balloon-expandable intracoronary stent developed by Palmaz and Schatz is undergoing clinical evaluation for use in unfavorable anatomic situations and in the prevention of restenosis. Because the stent's mechanism of action would suggest effectiveness in salvaging certain percutaneous transluminal coronary angioplasty (PTCA) failures, we retrospectively examined the results of emergency unplanned coronary artery stenting for failed PTCA procedures, including acute occlusion. Methods and Resus. The study population consisted of all US patients receiving emergency unplanned stent implantation in a nonrandomized fashion at seven centers over a 2½2-year period (n =56). All available medical records and angiograms were reviewed to determine retrospectively the reason for stenting: Group 1 consisted of 23 patients with a suboptimal angioplasty result; group 2 included patients with evidence of impending vessel closure after PTCA (n= 15); and group 3 were patients with frank acute occlusion after PTCA (n=18). The immediate and final (30-day) results of stenting were examined with respect to major complications, which included death, need for coronary artery bypass graft surgery, and occurrence of myocardial infarction. Finally, restenosis rates (>50o% stenosis) based on follow-up angiography were calculated. Baseline characteristics of the study population included a mean±SD age of 58±+11 years and a large prevalence of angiographic characteristics generally considered unfavorable for PTCA, which include lesion eccentricity (49o), intimal dissection (9%o), or angiographically visible thrombus (6%). After conventional balloon angioplasty, there was an increased incidence of intimal dissection (74%) and thrombus formation (38%1), and overall stenosis severity was unchanged (75±12% versus 70+27%, p=NS). Successful stent deployment was achieved in 55 (981%o) of 56 patients with initial success (freedom from death, surgery, and infarction) in 52 (93%) of 56 patients. The success rate at 1 month fell to 71% primarily because of the occurrence of subacute stent thrombosis (16%) and its associated complications. Overall, major complications occurred in 16 (29%) of 56 patients within 30 days. The only predictor of subacute stent thrombosis in multiple stepwise logistic regression analysis was the presence of angiographically visible thrombus after stenting (p=0.03). Angiographic restenosis was documented in eight (23%) of 35 eligible patients. Conclusions. Emergency stenting may be a useful and effective treatment for failed angioplasty. High initial success rates (>90%) can be achieved, but subsequent complications, often related to subacute thrombosis, occur in a substantial portion of patients. Patients who receive stents on an emergency basis, particularly those with previous acute occlusion, should be considered to be at greater than usual risk for complications and receive more careful anticoagulation and follow-up. (Circulation 1992;86:812-819) KEY WoRDs * restenosis * percutaneous transluminal coronary angioplasty * stents
T he immediate success rate of percutaneous transluminal coronary angioplasty (PTCA) generally exceeds 90%; however, failure to achieve an adequate result of .50% luminal diameter stenosis, All editorial decisions for this article, including selection of reviewers and the final decision, were made by a guest editor. This procedure applies to all manuscripts with authors from the University of California San Diego or UCSD Medical Center. From the Cardiovascular Division, Department of Medicine, Hospital of the University of Pennsylvania, University of Pennsylvania School of Medicine, Philadelphia, Pa. One of the authors (R.A.S.) is coinventor of the device described and holds an equity position with Johnson & Johnson. Address for reprints: Howard C. Herrmann, MD, 9 Founders Pavilion, Hospital of the University of Pennsylvania, 3400 Spruce Street, Philadelphia, PA 19104. Received March 9, 1992; revision accepted May 28, 1992.
caused by vasospasm, dissection, thrombus, and elastic recoil, may occur in as many as 10% of all procedures.1,2 Furthermore, acute occlusion occurs in 2-7% of all PTCA procedures and is associated with a high rate of complications, including death, myocardial infarction, and emergency coronary artery bypass graft surgery (CABG).1-6 Restenosis also may occur more frequently in patients with acute occlusion even after successful recanalization.7,8 The balloon-expandable intracoronary stent developed by Palmaz and Schatz recently has been introduced and is undergoing clinical evaluation for use in unfavorable anatomic situations and in the prevention of restenosis.9 The stent's mechanism of action would suggest that it might also be effective in salvaging certain PTCA failures by stabilizing dissections and opposing
Downloaded from http://circ.ahajournals.org/ at University of Pittsburgh--HSLS on March 16, 2015
Herrmann et al Emergent Balloon-Expandable Coronary Artery Stenting
elastic recoil and spasm. Several small and preliminary studies have reported on the use of the Palmaz-Schatz and other stents in emergency settings after failed PTCA.4 '0" In this cooperative effort from the US centers using the Palmaz-Schatz stent, we retrospectively analyzed the results, complications, and follow-up of nonprotocol, emergency, unplanned coronary stenting after PTCA, including failed procedures. Methods Study Population The study population consisted of all US patients receiving emergency unplanned implantation of one or more Palmaz-Schatz coronary artery stents at one of seven centers from November 1988 to July 1991. These patients were not participants in the usual stent protocols at the participating institutions and entered the laboratory with plans for conventional PTCA. Consent for emergency stenting was obtained in the catheterization laboratory just before stent implantation after consultation with the patient, their families and physicians, and a member of the institutional review board. Subsequently, a formal description of the indications and outcome of the procedure was forwarded to the institutional review board and the manufacturer. To further determine the reason for stenting in these nonprotocol patients, the medical record and angiograms were reviewed and subjects were retrospectively assigned to one of three groups: Group 1 consisted of patients receiving stents for a suboptimal angiographic angioplasty result considered unacceptable by the individual investigator; group 2 included patients with evidence for impending closure after PTCA, which was defined as a decrease of Thrombolysis in Myocardial Infarction trial (TIMI) flow grade .1 associated with clinical evidence of ischemia, which included chest pain and ECG changes; and group 3 were patients with acute occlusion after PTCA (TIMI flow grade 0 or 1 and .99% stenosis).
Definitions Immediate and final success were defined as successful stent deployment with establishment of TIMI grade 3 antegrade flow through the dilated segment and the absence of major complications during the procedure and within 30 days, respectively. Patients were considered to have unstable angina if they experienced symptoms at rest before the procedure. Stents were delivered hand-crimped on an angioplasty balloon before December 1990 (80%) and subsequently using a sheath delivery system. All patients received aspirin, dipyridamole, and dextran (10%) before stent deployment. Major complications included death, need for CABG, or the occurrence of Q and non-Q wave myocardial infarction. Restenosis stent
on a
was defined as .50% stenosis within the scheduled 6-month angiogram.
Angiographic Review All available angiograms (96%) were reviewed by two angiographers (H.C.H. and J.W.H.). Each film was analyzed for group assignment, baseline angiographic lesion characteristics including the presence of thrombus (filling defect with contrast agent on three sides), dissection (filling defect with extraluminal extravasation
TABLE 1. Baseline Characteristics Age (years) Sex (% male) Clinical history (n=51) Unstable angina Previous PTCA target lesion No. of stents placed Reason for stenting (n=56) Suboptimal result Impending closure Acute occlusion Vessel stented (n=56) LAD RCA LCx SVG Modified ACC/AHA class (n=56) A Bi B2 C
813
58+ 11 75 26 (51%) 16 (31%)
55/56 attempts 23 (41%) 15 (27%) 18 (32%) 24 (44%) 19 (35%) 7 (13%) 5 (9%) 10 (19%) 21 (40%) 17 (32%) 5 (9%)
PTCA, percutaneous transluminal coronary angioplasty; LAD, left anterior descending coronary artery; RCA, right coronary artery; LCx, left circumflex artery; SVG, saphenous vein graft; ACC, American College of Cardiology; AHA, American Heart Association.
of contrast agent), eccentricity, TIMI perfusion grade,12 modified American College of Cardiology-American Heart Association (ACC/AHA) score,13 and measured percentage stenosis. The same characteristics were also evaluated after the last balloon inflation before stent deployment and on the final angiogram after the stent was implanted. Quantitative coronary angiographic measurements (percent stenosis) were made using digital electronic calipers. Previous studies have shown such systems to have a high correlation with computerassisted methods with acceptably low intraobserver and interobserver variabilities.14'15
Statistics Results are expressed as mean±SD. Comparisons between groups were made by Scheffe's multiple comparison test, and subgroup comparisons were made by X2 analysis using standard formulas (STATVIEW statistical software, Calabresa, Calif.). Predictors of complications and restenosis were analyzed using multiple stepwise logistic regression of all demographic, procedural, and angiographic variables (spss statistical analysis software, Release 4 for the Macintosh, SPSS Inc., Chicago, Ill.). Results were considered significant if p
