Guidelines for percutaneous transluminal coronary angioplasty

Intracoronary ultrasound before coronary interventions: a prospective comparison of two different catheters

Intravascular ultrasound (IVUS) provides unique information about the coronary arterial wall that can be used to guide transcatheter therapy. In this prospective study, two different IVUS systems were compared with respect to feasibility of imaging before intervention and angiographic changes induced by the simple advancement of the catheter across the lesion. Eighty-five patients (mean age 59 +/- 10 yr, 11 female) were studied with IVUS before intervention. In 34 patients, a 4.8 F (1.6-mm) IVUS catheter was used (Group I), whereas in the remaining 51 patients, a 3.5 F (1.2-mm) IVUS catheter was used (Group II). Quantitative angiography was performed before and after the IVUS study to determine potential changes in lumen diameter. Clinical and angiographic characteristics were similar in the two groups. A successful IVUS interrogation of the target lesion was obtained more frequently in Group II (45/51 (88%) vs. 19/34 (56%) patients, P < 0.01). After the IVUS study, a change in minimal lumen diameter was seen in Group I (baseline 0.84 +/- 0.2 vs. final 1.17 +/- 0.2 mm, P < 0.001) and Group II patients (baseline 0.80 +/- 0.3 vs. final 1.03 +/- 0.4 mm, P < 0.01). In the 64 lesions successfully crossed, the absolute gain in lumen diameter was significantly higher in Group I (0.40 +/- 0.2 vs. 0.23 +/- 0.2 mm, P < 0.05). In addition, an inverse correlation was found between baseline minimal lumen diameter and the absolute lumen gain induced by the IVUS study in Group I (r = -0.47, P < 0.05) but not in Group II patients (r = -0.16, NS). Neither angiographic nor echogenic lesion characteristics were associated with the change in lumen diameter. When multivariate analysis was applied, catheter size was the only independent predictor of lumen gain induced by IVUS after adjustment. Thus, the advancement of IVUS catheters across severe coronary lesions induces significant angiographic changes consistent with plaque remodeling and a Dotter effect. The use of smaller catheters not only allows a higher number of lesions to be studied before intervention, but also lessens the mechanical disruption of the plaque, yielding a more accurate and veracious picture of baseline plaque characteristics.

Ticlopidine and aspirin pretreatment reduces coagulation and platelet activation during coronary dilation procedures

OBJECTIVES

It is unknown whether a therapeutic combination of aspirin (ASA) and ticlopidine might effectively decrease activation of hemostasis.

BACKGROUND

Percutaneous transluminal coronary angioplasty (PTCA), rotational atherectomy and stent implantation are procedures that fracture or ablate endothelium and plaque, a situation that activates hemostasis.

METHODS

In 85 patients undergoing PTCA for a 77.8 +/- 1% stenosis, we measured markers of coagulation and platelet activation (thrombin-antithrombin complexes [TAT], prothrombin fragment 1 + 2 [F1 + 2] serotonin and the presence of circulating activated platelets reacting with monoclonal antibodies against glycoproteins exposed on platelet membranes). Blood samples were drawn from a peripheral vein and from the coronary ostium before the procedures. Both immediately and 10 min after angioplasty, and 10 min afterward, samples were collected from a probing catheter (0.018 in, [0.46 cm]) positioned beyond the stenosis. All patients were being treated with antianginal drugs and ASA, 250 mg/day. Seventy of them had taken ticlopidine, 250 mg, twice daily for < or = 1 day (< or = 24 h) (n = 28) or for > or = 3 days (> or = 72 h) (n = 42). Heparin (150 U/kg) was administered before angioplasty. Thirty patients underwent PTCA; 15 of them were not treated with ticlopidine and 15 were given ticlopidine (> or = 72 h). Thirty-five patients had stent implantation, 20 rotational atherectomy.

RESULTS

Before and during the procedures, there was greater thrombin generation (expressed by higher TAT and F1 + 2 plasma levels) in patients not taking ticlopidine or taking it for < or = 24 h (p < 0.05). Platelet activation and plasma serotonin levels were also significantly higher in the no ticlopidine or < or = 24-h ticlopidine groups.

CONCLUSIONS

The combined use of ticlopidine, ASA and heparin effectively controls activation of coagulation in patients with stable or unstable angina undergoing coronary dilation.

Fish oils and low-molecular-weight heparin for the reduction of restenosis after percutaneous transluminal coronary angioplasty. The EMPAR Study

BACKGROUND

Percutaneous transluminal coronary angioplasty (PTCA) is complicated by restenosis within 6 months in > 40% of patients. Theoretical, animal experimental, and human epidemiological and clinical trial findings have suggested that fish oils (n-3) might reduce restenosis. Low-molecular-weight heparin (LMWH) has reduced cellular proliferation and restenosis in several experimental systems.

METHODS AND RESULTS

We randomized 814 patients to fish oils (5.4 g n-3 fatty acids) or placebo a median of 6 days before PTCA and continued for 18 weeks. At the time of sheath removal, 653 patients with at least one successfully dilated lesion were randomized to LMWH (30 mg SC BID) or control for 6 weeks in a 2 x 2 factorial design. Follow-up with quantitative coronary angiography (QCA; target, 18 weeks) was interpretable on 96% of these patients. Restenosis rates per patient were for n-3, 46.5%; placebo, 44.7%; LMWH, 45.8%; and control, 45.4%. Restenosis rates per lesion were for n-3, 39.7%; placebo, 38.7%; LMWH, 38%; and control, 40.4%. At follow-up QCA, mean minimal lumen diameters were (mm) for n-3, 1.12; placebo, 1.10; LMWH, 1.12; and control, 1.10. Fifteen percent of patients permanently discontinued n-3/placebo before study completion, and 21% of patients discontinued LMWH early. There were no significant differences in the occurrences of ischemic events. Bleeding was more common with LMWH, usually was mild, and led to early discontinuation of study medication in only 0.9% of patients. Gastrointestinal side effects were more common in patients receiving n-3 than placebo.

CONCLUSIONS

There is no evidence for a clinically important reduction of PTCA restenosis in this trial by either n-3 or LMWH. Evaluation of the results for n-3 in the context of previously published data on the reduction of PTCA restenosis indicates that n-3 is not efficacious and that further trials are unwarranted.

Initial cost of primary angioplasty for acute myocardial infarction

OBJECTIVES

We sought to evaluate the initial economic cost of primary angioplasty for acute myocardial infarction under varying assumptions about whether a cardiac catheterization laboratory exists, whether services are provided during night and weekend hours and how cardiovascular surgical backup is arranged.

BACKGROUND

Primary angioplasty for acute myocardial infarction has resulted in clinical outcomes superior or equal to those obtained with thrombolysis in recent studies, but its future implementation depends greatly on its cost and cost-effectiveness. There is a gap in knowledge about the true economic costs of this procedure, and understanding costs under a variety of hypothetic scenarios is important in planning whether and how the procedure should be offered to broad groups of patients.

METHODS

A generalizable spreadsheet model was constructed to calculate the cost of primary angioplasty at a single hospital with assumptions based on data from a large nonprofit health maintenance organization (Kaiser Permanente). The following baseline assumptions were made: 1) A total of 200 patients with myocardial infarction presented to the hospital each year; 2) primary angioplasty was offered for 10 years; 3) the hospital had a cardiac catheterization laboratory; 4) costs of night call for technical personnel and cardiovascular surgical backup were already covered. Other scenarios were modeled to represent different assumptions about existing resources.

RESULTS

Under the baseline assumptions, primary angioplasty cost $1,597/procedure. If night call for technical personnel were a new expense, the average cost would be > or = $3,206. If a new cardiac catheterization laboratory needed to be built, costs would range from $3,866 to $14,339/procedure, depending on how cardiovascular surgical backup was provided. Results were sensitive to assumptions about the annual volume of myocardial infarctions, the number of years the procedure was offered and the costs of labor, construction and equipment.

CONCLUSIONS

The initial cost of providing primary angioplasty for acute myocardial infarction varies greatly, depending on the setting in which it is provided. To provide information for clinical policy decisions, a cost-effectiveness model is needed that combines these initial costs with data on survival, quality of life and rates and costs of subsequent cardiac procedures.

Contemporary practice of coronary revascularization in U.S. hospitals and hospitals participating in the bypass angioplasty revascularization investigation (BARI)

OBJECTIVES

To assess generalizability of the Bypass Angioplasty Revascularization Investigation (BARI), we conducted a separate study comparing revascularization in U.S. and BARI hospitals.

BACKGROUND

The BARI trial is a multicenter investigation comparing initial revascularization with percutaneous transluminal coronary angioplasty and coronary bypass graft surgery in patients with symptomatic multivessel coronary disease.

METHODS

All revascularization procedures during 5 consecutive workdays were surveyed at 75 U.S. hospitals offering coronary angioplasty and bypass surgery and at all BARI hospitals. Data collected were demographics, extent of disease and type of current and previous revascularization.

RESULTS

At both U.S. and BARI hospitals, 57% of all revascularization procedures were coronary angioplasty and 43% were bypass surgery. The U.S. hospitals had more patients with single-vessel disease, acute myocardial infarction and primary procedures. Other characteristics were similar. The majority of revascularization procedures were angioplasty for single-vessel disease (U.S. 32% vs. BARI 25%) and bypass surgery for triple-vessel disease (U.S. 31% vs. BARI 31%). Overall, the choice between bypass surgery and angioplasty was similar in BARI and U.S. hospitals (adjusted odds ratio [OR] 1.0, p = 0.914). However, older patients were more likely and younger patients less likely to undergo bypass surgery in BARI versus U.S. hospitals (older patients: adjusted OR 1.6, p = 0.031; younger patients: adjusted OR 0.6, p = 0.028). The BARI protocol would have excluded 65% of all candidates for revascularization, for whom indications already exist for angioplasty or bypass surgery, and another 23%, for whom angioplasty would be contraindicated for individual lesions.

CONCLUSIONS

Patients undergoing coronary revascularization in BARI and U.S. hospitals were generally similar, as was the choice between types of revascularization. Results from the BARI trial apply to approximately 300 (12%) candidates for coronary revascularization/workday.

Comparison of angioscopy, intravascular ultrasound imaging and quantitative coronary angiography in predicting clinical outcome after coronary intervention in high risk patients

OBJECTIVES

The purpose of this study was to identify qualitative or quantitative variables present on angioscopy, intravascular ultrasound imaging or quantitative coronary arteriography that were associated with adverse clinical outcome after coronary intervention in high risk patients.

BACKGROUND

Patients with acute coronary syndromes and complex lesion morphology on angiography are at increased risk for acute complications after coronary angioplasty. Newer devices that primarily remove atheroma have not improved outcome over that of balloon angioplasty. Intravascular imaging can accurately identify intraluminal and intramural histopathologic features not adequately visualized during coronary arteriography and may provide mechanistic insight into the pathogenesis of abrupt closure and restenosis.

METHODS

Sixty high risk patients with unstable coronary syndromes and complex lesions on angiography underwent angioscopy (n = 40) and intravascular ultrasound imaging (n = 46) during interventional procedures. In 26 patients, both angioscopy and intravascular ultrasound were performed in the same lesion. All patients underwent off-line quantitative coronary arteriography. Coronary interventions included balloon (n = 21) and excimer laser (n = 4) angioplasty, directional (n = 19) and rotational (n = 6) atherectomy and stent implantation (n = 11). Patients were followed up for 1 year for objective evidence for recurrent ischemia.

RESULTS

Patients whose clinical presentation included rest angina or acute myocardial infarction or who received thrombolytic therapy within 24 h of procedure were significantly more likely to experience recurrent ischemia after intervention. Plaque rupture or thrombus on preprocedure angioscopy or angioscopic thrombus after intervention were also significantly associated with adverse outcome. Qualitative or quantitative variables on angiography, intravascular ultrasound or off-line quantitative arteriography were not associated with recurrent ischemia on univariate analysis. Multivariate predictors of recurrent ischemia were plaque rupture on preprocedure angioscopy (p < 0.05, odds ratio [OR] 10.15) and angioscopic thrombus after intervention (p < 0.05, OR 7.26).

CONCLUSIONS

Angioscopic plaque rupture and thrombus were independently associated with adverse outcome in patients with complex lesions after interventional procedures. These features were not identified by either angiography or intravascular ultrasound.

Periprocedural Doppler coronary blood flow predictors of myocardial perfusion abnormalities and cardiac events after successful coronary interventions

Thirty-four consecutive patients had coronary flow velocity assessed under basal and hyperemic conditions in the proximal and distal coronary artery, followed by rest-stress technetium 99m sestamibi myocardial tomography within 3 months of successful coronary angioplasty. In spite of significant angiographic improvement, 29% of patients had a persistent reversible myocardial perfusion defect associated with a residual abnormality of the proximal-to-distal coronary average peak velocity ratio (p/d APV = 2.2 +/- 1.5 vs 1.1 +/- 0.6; p = 0.02). Patients with an abnormal p/d APV ratio (>1.7) had more numerous angioplasty-zone perfusion defects (4.2 +/- 3.3 vs 0.8 +/- 2.0; p = 0.005). Multivariable analysis of clinical, angiographic, coronary flow, and scintigraphic data demonstrated that the relative risk of cardiac events (n = 11) was greatest in patients with a reversible angioplasty-zone perfusion defect (relative risk, 5.5), poststenotic coronary flow reserve <2.0 (relative risk, 8.3) and p/d APV ratio >1.7 (relative risk, 6.2). Residual basal coronary flow-velocity abnormalities are significant physiologic correlates of stress-induced myocardial perfusion defects and are a prognostic covariable associated with future ischemic cardiac events.

Inter- and intra-observer variability in the qualitative categorization of coronary angiograms

The ABC classification of the American College of Cardiology and the American Heart Association is a commonly used categorization to estimate the risk and success of intracoronary intervention, as well as the probability of restenosis. To evaluate the reliability of qualitative angiogram readings, we randomly selected 200 films from single lesion angioplasty procedures. A repeated visual assessment (> or = 2 months interval) by two independent observers resulted in kappa values of inter and intra-observer variability for the ABC lesion classification and for all separate items that compile it. Variability in assessment is expressed in percentage of total agreement, and in kappa value, which is a parameter of the agreement between two or more observations in excess of the chance agreement. Percentage of total agreement and kappa value was 67.8% and 0.33 respectively for the ABC classification, indicating a poor agreement. Probably this is due to the deficiency of strict definitions. Further investigation has to demonstrate whether improvement can be achieved using complete and detailed definitions without ambiguity, and consensus after panel assessment.

Comparison of percutaneous transluminal coronary angioplasty outcome and hospital costs for low-volume and high-volume operators

Whether higher operator case volume is associated with improved percutaneous transluminal coronary angioplasty (PTCA) clinical and cost outcomes is the subject of this study. Hospital volume-related improvement in clinical outcomes has been shown for coronary artery bypass grafting (CABG) and PTCA. Physician case volume-related differences in clinical outcomes have not been clearly demonstrated, and differences in hospital costs have not been examined. For clinical and cost outcomes, risk-adjusted analysis of differences in PTCA outcomes has not been reported. In addition, controversy exists about the appropriate annual case volume considered adequate to maintain skills and achieve optimal clinical outcomes in performing PTCA procedures. We studied 2,350 PTCAs performed between March 1, 1991, and February 28, 1994. Physicians were divided into 2 volume groups: high (>50 cases/year) and low (<50 cases/year). The rate of emergency CABG after PTCA was 2.1% for high- and 3.9% for low-volume operators (p = 0.009). Hospital morbidity associated with PTCA was lower in high-than in low-volume operators (6.46% vs 10.73%, p <0.001). The risk-adjusted ratios for emergency CABG and morbidity were 2.05 (p = 0.005) and 1.79 (p <0.001), respectively. The length of stay averaged 4.07 +/- 4.54 days for high- and 4.49 +/- 4.33 days for low-volume operators (p = 0.003). Hospital costs averaged $7,977 +/-$7,269 for high- and $8,278 +/- $6,289 for low-volume operators (p = 0.065). The risk adjusted ratio was 1.091 (p = 0.004) for length of stay and 1.050 (p = 0.029) for cost. Thus, PTCA performed by high-volume operators is significantly less likely to require emergency CABG and is also significantly associated with lower hospital morbidity, shorter hospital length of stay, and lower hospital costs.

Subacute stent thrombosis: evolving issues and current concepts

During percutaneous coronary revascularization, intracoronary stents are effective in the treatment of abrupt vessel closure and improvement of suboptimal angioplasty results, and compared to balloon angioplasty, they reduce stenosis recurrence. Opposing these benefits, subacute thrombosis of stents is associated with a substantial increase in periprocedural morbidity and mortality. To review factors associated with stent thrombosis and to study the impact of evolving procedural techniques on the incidence of stent thrombosis, we reviewed all English articles from MEDLINE (1988 to 1995) with key words "stent" and "thrombosis." Stent registry data and recent abstracts from scientific meetings were also reviewed. Factors related to the clinical setting, the lesion, the stent and the procedural technique that affect the risk of stent thrombosis were identified. Sixty clinical studies were reviewed and include 7,914 patients receiving intracoronary stents. Studies were separated into those reporting stents placed emergently or electively without adjunct high-pressure balloon inflations, stents placed in saphenous vein graft conduits, and stents placed with high-pressure balloon inflations but without subsequent oral anticoagulants. Overall, subacute thrombosis was substantially higher in stents placed emergently (10.1%) compared to those placed electively (4.3%). Among contemporary trials employing high-pressure balloon inflations, the rate of stent thrombosis appears markedly lower (1.3%) despite reduced postprocedural anticoagulation. Taken together, these studies suggest factors associated with a heightened risk of stent thrombosis, many of which can be avoided with proper case selection and contemporary techniques.

Cost-effectiveness of coronary angioplasty versus medical treatment: the impact of cost-shifting

BACKGROUND

Coronary angioplasty (PTCA) offers improved symptom control over medical treatment in patients with stable angina and single-vessel disease. However, it is uncertain if PTCA is more cost-effective. Cost-shifting could also influence the provision of PTCA.

METHODS

Data from the only randomised trial comparing PTCA to medical therapy (ACME study) were used with costs from an Australian teaching hospital to estimate the costs and freedom from angina in 100 patients over three years. The incremental cost-effectiveness of PTCA, and the potential for cost-shifting were also examined.

RESULTS

Although the total cost of treating 100 patients over three years with PTCA ($678,978) was higher than a medical strategy ($631,078), PTCA was more cost-effective ($10,930 versus $12,682 per patient free of angina). The incremental cost-effectiveness of PTCA ($3875 per extra patient free of angina) was also substantially less than the cost of the medical strategy. These should be considered crude estimates as they were based on limited data on resource use. The hospital could reduce costs by pursuing a medical strategy, but 54% of the savings would result from shifting the cost of treating patients to the Federal Government and patients. By performing PTCA on privately insured rather than Medicare patients, the hospital could shift $29,876 per 100 patients to the Federal government and private insurance funds.

CONCLUSIONS

From society's perspective, PTCA may be more cost-effective than a medical strategy. However, the financial interests of the hospital are best served by limiting PTCA or restricting PTCA to privately insured patients. Cost-shifting may have a major impact on the provision of PTCA. The costs of providing medical services need to be weighed against the cost of not providing them.

Coronary angioplasty of branch vessels associated with an extreme angle take-off

Stenoses in branch vessels which originate at acute angle to the main vessel represent a technically challenging anatomy for the performance of balloon angioplasty [PTCA]. We report a novel technique utilizing a distally placed perfusion balloon that facilitated guidewire placement and subsequent balloon angioplasty of a branch vessel stenosis.

Guide wire extension may not be essential to pass an over-the-wire balloon catheter

The ability to pass an angioplasty balloon catheter over a regular length free guidewire can be advantageous in certain circumstances. This procedure was performed successfully in 99 consecutive patients without any complications. There was improved tactile sense of the lesion and improved dye delivery without the necessity of resorting to the use of extension wires or magnet exchange device. When performed while observing the required precautions this is a safe procedure.

Coronary angioplasty, atherectomy and bypass surgery in cardiac transplant recipients

OBJECTIVES

This study sought to analyze the outcomes of revascularization procedures in the treatment of allograft coronary disease.

BACKGROUND

Allograft vasculopathy is the main factor limiting survival of heart transplant recipients. Because no medical therapy prevents allograft atherosclerosis, and retransplantation is associated with suboptimal allograft survival, palliative coronary revascularization has been attempted.

METHODS

Thirteen medical centers retrospectively analyzed their complete experience with percutaneous transluminal coronary angioplasty, directional coronary atherectomy and coronary bypass graft surgery in allograft coronary disease.

RESULTS

Sixty-six patients underwent coronary angioplasty. Angiographic success (< or = 50% residual stenosis) occurred in 153 (94%) of 162 lesions. Forty patients (61%) are alive without retransplantation at 19 +/- 14 (mean +/- SD) months after angioplasty. The consequences of failed revascularization were severe. Two patients sustained periprocedural myocardial infarction and died. Angiographic restenosis occurred in 42 (55%) of 76 lesions at 8 +/- 5 months after angioplasty. Angiographic distal arteriopathy adversely affected allograft survival. Eleven patients underwent directional coronary atherectomy. Angiographic success occurred in 9 (82%) of 11 lesions. Two periprocedural deaths occurred. Nine patients are alive without transplantation at 7 +/- 4 months after atherectomy. Bypass graft surgery was performed in 12 patients. Four patients died perioperatively. Seven patients are alive without retransplantation at 9 +/- 7 months after operation.

CONCLUSIONS

Coronary revascularization may be an effective palliative therapy in suitable cardiac transplant recipients. Angioplasty has an acceptable survival in patients without angiographic distal arteriopathy. Because few patients underwent atherectomy and coronary bypass surgery, assessment of these procedures is limited. Angiographic distal arteriopathy is associated with decreased allograft survival in patients requiring revascularization.

Percutaneous transluminal coronary angioplasty failures in patients with multivessel disease. Is there an increased risk?

In recent years, there has been a nationwide trend toward performing percutaneous transluminal coronary angioplasty in patients with multivessel coronary artery disease. The clinical course of 57 consecutive patients who required emergency first-time coronary artery bypass grafting operations were reviewed to assess for difference in outcome between the 28 patients (49%) with single-vessel disease and the 29 patients (51%) with multivessel disease. The two groups were similar in preoperative characteristics except for a higher proportion of chronic obstructive pulmonary disease in the patients with multivessel disease (p = 0.03). Twice as many patients with multivessel disease were in shock (single-vessel disease = 4 [14%], multivessel disease = 8 [28%], p = not significant) en route to the operating room and significantly more patients with multivessel disease required on-going cardiopulmonary resuscitation (single-vessel disease = 0 [0%], multivessel disease = 5 [17%], p = 0.03). Significantly more coronary artery bypass grafts were placed in the patients with multivessel disease (single-vessel disease = 1.5 +/- 0.6, multivessel disease = 2.9 +/- 0.7, p < 0.01), which required longer aortic clamping time (p = 0.02) and cardiopulmonary bypass time (p < 0.01). There were seven postoperative deaths; all but one occurred in patients with multivessel disease (single-vessel disease = 1 [4%], multivessel disease = 6 [21%], p = 0.05). According to multivariate analysis, incremental risk factors of mortality were preoperative shock (p < 0.01), urgent or emergency percutaneous transluminal coronary angioplasty (p = 0.06), and multivessel disease (p = 0.12). Despite a similar incidence of myocardial infarction (single-vessel disease = 8 [29%], multivessel disease = 12 [41%], p = not significant), patients with multivessel disease had a higher incidence of cardiac morbidity (single-vessel disease = 4 [14%], multivessel disease = 11 [38%], p = 0.04) and noncardiac morbidity (single-vessel disease = 4 [14%], multivessel disease = 12 [41%], p = 0.02). By multivariate analysis, incremental risk factors of morbidity were preoperative shock (p < 0.01), multivessel disease (p = 0.02), and ejection fraction < 50% (p = 0.07). In the subset of patients with multivessel disease, preoperative shock, ejection fraction < 50, and an age of 60 years or greater were associated with higher morbidity and mortality. In conclusion, the risk of percutaneous transluminal coronary angioplasty failure is considerably higher in patients with multivessel disease. In certain subsets of patients with multivessel disease, coronary artery bypass grafting would be a safer procedure when compared with percutaneous transluminal coronary angioplasty for initial myocardial revascularization.

Angioscopic findings during coronary angioplasty of coronary occlusions

OBJECTIVES

This study sought to elucidate angioscopic findings in totally occluded vessels before and after intervention.

BACKGROUND

Coronary angioscopy allows direct visualization of the lumen surface of the coronary arteries; however, the utility of coronary angioscopy during coronary angioplasty of vessels with a total occlusion is unknown.

METHODS

Twenty-one consecutive patients (mean [+/- SD] 58 +/- 9 years, range 39 to 77; 3 women, 18 men) undergoing dilation of an occluded vessel were studied with coronary angioscopy. Occlusions were classified as functional in 8 patients (Thrombolysis in Myocardial Infarction [TIMI] flow grade 1) and anatomic in 13 (TIMI flow grade 0). Once the guide wire had crossed the occlusion, coronary angioscopy was attempted before and after angioplasty.

RESULTS

In all patients, coronary angioscopy before dilation visualized protruding material occluding the coronary lumen where the guide wire was wedged. The occlusion consisted of red thrombus in 19 patients (90%) (2 with isolated occlusive thrombus, 17 with thrombus associated with atherosclerotic plaque) and protruding yellow plaque in 2 patients (10%). However, on angiography only 7 occlusions (33%) had data consistent with thrombus (p < 0.01 vs. coronary angioscopy). Successful dilation was obtained in 20 patients. After dilation, coronary angioscopy was repeated in 18 patients, revealing residual thrombus with plaque in 16 (89%) and a residual yellow plaque in 2. In addition, coronary angioscopy revealed coronary dissections in 13 patients (72%); however, angiography revealed dissections only in 10 patients (55%) and residual thrombus in 2 (10%) (p < 0.001). In one patient, coronary angioscopy visualized silent distal embolization of a red thrombus not previously recognized on angiography.

CONCLUSIONS

Before intervention, coronary angioscopy provides unique insights into the pathologic substrate of occluded coronary vessels. An occlusive plaque with thrombus is the most common underlying substrate in these lesions. After successful dilation, angiographically silent mural thrombus is seen in most patients. This information could be used to assist in the selection of candidates and type of coronary interventions and could also prove to be of prognostic value in patients with occluded vessels.

Angioplasty in acute myocardial infarction

The results of early trials indicate that angioplasty during the first hours after MI onset has a lower incidence of reinfarction, intracranial hemorrhage, and death than does thrombolysis. In fact, results have been so good that the procedure has been approved for use in hospitals that do not have coronary bypass backup programs. Is angioplasty about to become the intervention of choice in acute MI?

Distal embolization is common after directional atherectomy in coronary arteries and saphenous vein grafts

Coronary embolization is a complication of coronary intervention procedures. The incidence, predictors, and clinical significance of this phenomenon during directional atherectomy were examined in 111 consecutive patients who underwent directional atherectomy to 120 lesions. Distal embolization occurred in 31 (28%) of the patients. It was noted mainly in the saphenous vein graft group of patients (12 [48%] of 25) versus the native coronary group (19 [22% of 86]; p = 0.01). Clinical predictors were age and de novo lesions. Morphologic predictors were larger artery size, larger postprocedure minimal luminal diameter, calcific lesions, and type C lesions. The only difference in clinical outcome was a longer hospitalization in the distal embolization group with 3.9 +/- 3.7 days versus the rest of the patients 2.4 +/- 2.4 days (p = 0.01). In the majority of patients there was no significant adverse clinical outcome.

Effectiveness of percutaneous transluminal coronary angioplasty for patients with medically refractory rest angina pectoris and high risk of adverse outcomes with coronary artery bypass grafting

This study was undertaken to test the hypothesis that percutaneous transluminal coronary angioplasty (PTCA) is a reasonable alternative to coronary artery bypass grafting (CABG) for some high-risk patients with medically refractory rest angina. Over a 5-year period, 1 operator at a tertiary Veterans Affairs Medical Center performed angioplasty on 624 patients, of whom 441 had unstable angina. Of these 441 patients, 288 had rest angina and 225 had medically refractory rest angina. Medically refractory unstable angina was defined as reversible myocardial ischemia occurring at rest in an intensive care unit setting with low flow oxygen despite the following medications: (1) oral aspirin, intravenous heparin, or both; (2) some combination of beta blocker, calcium blocker, and/or nitrate so that resting heart rate is < 70 beats/min or resting blood pressure < 140 mm Hg, or both. There were 207 patients with medically refractory rest angina who had > or = 1 of the following characteristics predictive of a more than twofold increased risk of operative death at CABG: age > 70 years, prior CABG, recent myocardial infarct, need for intravenous nitroglycerin, need for intraaortic balloon pump, and left ventricular ejection fraction < 0.35. Of these 207 patients, 11 died (5%) during index hospitalization, 196 (95%) were discharged, and 186 (90%) went home angina free. There were 2 emergency CABGs and 9 acute myocardial infarctions. At follow-up (3 to 60 months, average 24), there were 27 late deaths (for a total of 38 [18%]), 8 (4%) late CABGs, and 44 (21%) late PTCAs (with 17 [8%] late myocardial infarctions). The 2-year mortality of 18% for this cohort is comparable to a 21% 2-year mortality observed in a group of 1,073 "high-risk" patients who underwent CABG in the Veterans Affairs Medical Center from 1987 to 1988. These data support the hypothesis that PTCA provides an alternative to CABG in some high-risk patients with medically refractory rest angina.

HCFA's Health Care Quality Improvement Program and the Cooperative Cardiovascular Project

The Health Care Financing Administration (HCFA) is changing the direction of its quality assessment and improvement program from one that tries to identify and cull "bad apples" to one that tries to improve the mainstream of care. This strategy change is known as the "Health Care Quality Improvement Program." An important aspect of this strategy change is to develop a partnership with providers that will ensure the provision of quality improvement information that is valid and useful to them. The Health Care Quality Improvement Program consists of both quality improvement projects and a series of quality indicators. The Medicare Quality Indicator System will develop a small number of indicators or appropriateness criteria for each major medical condition that affects Medicare beneficiaries. This national monitoring system has three primary goals: (1) to track trends in the quality of care over time and in variations in the quality of care across regions; (2) to provide the basis for making decisions on where it would be appropriate to carry out quality-of-care improvement projects; and (3) to support the execution of these projects. Quality improvement projects are cooperative efforts designed to improve a specific aspect of care. The Cooperative Cardiovascular Project is an early quality improvement project focusing initially on acute myocardial infarction; it will later focus on coronary artery bypass grafting and percutaneous coronary artery angioplasty.

Randomized prospective evaluation of prolonged versus abbreviated intravenous heparin therapy after coronary angioplasty

OBJECTIVES

This study was designed to prospectively evaluate the routine use of continuous heparin therapy after successful uncomplicated coronary angioplasty.

BACKGROUND

The use of such therapy varies among institutions and may increase the incidence of complications. Evaluation of the risks and benefits of abbreviated heparin therapy combined with early sheath removal after coronary angioplasty is necessary to determine optimal postprocedure care.

METHODS

We prospectively studied 284 patients who were scheduled for elective coronary angioplasty. Historical, clinical, physiologic and angiographic data were gathered. All patients received an initial bolus of heparin and then were randomized during the procedure to receive either no additional heparin therapy or an adjusted 24-h infusion. On the basis of specific criteria, additional heparin was not withheld if procedural results suggested an increased risk for complications.

RESULTS

Two hundred thirty-eight patients completed the study; 46 others were excluded in the catheterization laboratory because of unfavorable procedural results. The patients with abbreviated (n = 118) and 24-h (n = 120) therapy did not differ with respect to demographic and angiographic findings. However, the former had fewer bleeding complications (0% vs. 7%, p < 0.001) and were discharged earlier (mean +/- SD 23 +/- 11 h vs. 42 +/- 24 h, p < 0.001). One patient in this group had a major complication shortly after angioplasty. The mean savings in hospital charges in the abbreviated therapy group was $1,370 ($6,093 +/- $1,772 vs. $7,463 +/- $1,782, p < 0.001).

CONCLUSIONS

Omission of routine heparin therapy after successful coronary angioplasty reduces bleeding complications without increasing patient risk. Earlier discharge and significant cost savings are possible under proper conditions.

A randomized study of coronary angioplasty compared with bypass surgery in patients with symptomatic multivessel coronary disease. German Angioplasty Bypass Surgery Investigation (GABI)

BACKGROUND

The standard treatment for patients with symptomatic multivessel coronary artery disease is coronary-artery bypass grafting (CABG). Percutaneous transluminal coronary angioplasty (PTCA) is widely used as an alternative approach to revascularization, but a systematic comparison of the two procedures is needed. We compared the outcomes in patients one year after complete revascularization with CABG or PTCA.

METHODS

A total of 8981 patients with multivessel coronary disease were screened at eight clinical sites, and 359 patients were randomly assigned to undergo CABG (177 patients) or PTCA (182 patients). Enrollment required that complete revascularization of at least two major vessels supplying different myocardial regions be deemed clinically necessary and technically feasible.

RESULTS

Among the patients in the CABG group, an average of 2.2 +/- 0.6 vessels were grafted, and among those in the PTCA group, 1.9 +/- 0.5 vessels were dilated. After CABG, hospitalization was longer (median, 19, as compared with 5 days for PTCA), and Q-wave myocardial infarction in relation to the procedure was more frequent (8.1 percent, as compared with 2.3 percent after PTCA; P = 0.022), whereas in-hospital mortality did not differ significantly between the two groups (2.5 percent in the CABG group and 1.1 percent in the PTCA group). At discharge 93 percent of the patients in the CABG group were free of angina, as compared with 82 percent of those in the PTCA group (P = 0.005). During the first year of follow-up, further interventions were necessary in 44 percent of the patients in the PTCA group (repeated PTCA in 23 percent, CABG in 18 percent, and both in 3 percent) but in only 6 percent of the patients in the CABG group (repeated CABG in 1 percent and PTCA in 5 percent; P < 0.001). Seventy-four percent of the patients in the CABG group and 71 percent of those in the PTCA group were free of angina one year after treatment. Exercise capacity improved similarly in both groups. However, 22 percent of the CABG group, as compared with only 12 percent of the PTCA group, did not require antianginal medication (P = 0.041).

CONCLUSIONS

In selected patients with multivessel coronary disease, PTCA and CABG as initial treatments resulted in equivalent improvement in angina after one year. However, in order to achieve similar clinical outcomes, the patients treated with PTCA were more likely to require further interventions and antianginal drugs, whereas the patients treated with CABG were more likely to sustain an acute myocardial infarction at the time of the procedure.

Health care technology in the United States

The US health care system reflects the free market of the US economy--there is no fixed budget and no limit on expenditures in the loosely structured matrix of largely private-sector health industry components. Mainly because of the inaccessibility of adequate health care for a large segment of the population, and because of the enormous cost of care threatens financial ruin for many more people, the first major reform of the system was debated in Congress for most of 1994, though, in the end, no leglislation was passed. One focus of the debate on spending has been the problem of excessive use of expensive medical technology and the need for some control, which, by and large, is lacking in the existing system. Health care technology assessment itself is a thriving industry in the United States, used by government, insurers, medical societies, hospitals, and other groups for their own purposes. At the national policy level, few opportunities for technology assessment to affect the health care industry exist, so most effort is directed at trying to affect medical practice at the level of the individual hospital and practitioner. The discernible effect of technology assessment has been minimal.

Predicting the risk of abrupt vessel closure after angioplasty in an individual patient

OBJECTIVES

We proposed to examine the relation between angiographic morphologic characteristics and abrupt closure after coronary angioplasty and to develop an empirically based risk stratification system.

BACKGROUND

Certain lesion morphologic characteristics are associated with higher rates of abrupt closure after coronary angioplasty. Previous approaches have been limited by relatively small sample sizes and an inability to combine multiple characteristics to predict risk in an individual patient.

METHODS

Lesion morphology was determined for 779 lesions in 658 patients undergoing an elective first angioplasty. Abrupt closure occurred in 63 lesions (8.1%). Variables associated with abrupt closure were identified by univariate and stepwise multiple logistic regression analysis, and internal validity was assessed by use of bootstrapping. An empirically based scoring system was developed by assigning different weights to each predictive characteristic and was then validated.

RESULTS

Almost all lesion characteristics previously labeled "adverse" were associated with an increased risk of abrupt closure, but only total occlusion, location at a branch point, increasing lesion length, evidence for thrombus and right coronary artery location were statistically significant independent predictors. Despite the large sample size, the study was underpowered to detect even a 50% increase in risk with many characteristics. Using a scoring system, we assigned each lesion a specific risk of abrupt closure. The distribution of risk was broad, with 20% of patients having < or = 2.5% risk and 25% having > 10% risk. Internal validation techniques revealed that when 10% of patients were randomly eliminated from the sample in multiple iterations, the risk estimates varied, again pointing to the need for a larger sample.

CONCLUSIONS

Empirically based weighting of lesion characteristics could quantify the risk of abrupt closure for individual patients, but a very large sample will be required to understand the interplay of complex lesion characteristics in altering expected outcomes.

Task Force 4: The relationship between cardiovascular specialists and generalists

1. An imbalance between generalists and cardiovascular subspecialists exists that will require decades to correct. We question the validity of the 50:50 generalist/specialist ratio in view of current practice patterns for cardiology. 2. There has been a large increase in the number of cardiovascular specialists in the past 30 years that will continue if training programs remain at their current size. 3. Cardiovascular specialists provide a substantial amount of inpatient care, care to older patients and care to those with cardiovascular symptoms, although generalists actually provide the majority of office-based cardiovascular care. 4. A significant portion of cardiovascular specialist care can be classified as comprehensive care to patients with and without cardiovascular disease. 5. Most generalists and cardiovascular specialists do not perceive a need for additional cardiovascular specialists. 6. Many providers perform cardiovascular procedures at levels below the recommended threshold for maintenance of clinical competence. 7. Managed care may result in a reduced demand for cardiovascular specialists. 8. If cardiovascular specialists provide general care, it may not be assumed that previous training prepares them for generalist practice. 9. The appropriate boundaries of cardiovascular care between generalists and cardiovascular specialists are indistinct. They are defined somewhat by the training programs from which the generalists graduate. 10. Many generalists have deficiencies in basic skills in clinical cardiology. 11. Desirable interactions between generalists and cardiovascular specialists involve referral of patients in both directions to the provider who can give care to a given patient, at a given time, with the best outcome and lowest cost.(ABSTRACT TRUNCATED AT 250 WORDS)

Current status of myocardial perfusion imaging after percutaneous transluminal coronary angioplasty

Controversy exists with regard to the diagnostic accuracy and optimal technique of myocardial perfusion imaging after coronary angioplasty. Exercise treadmill testing is inexpensive, with adequate predictive value for restenosis and clinical events in patients with single-vessel coronary angioplasty with a normal rest electrocardiogram (ECG). Myocardial tomography has advantages for assessing patients with multivessel coronary angioplasty. Exercise stress imaging is generally preferable to pharmacologic stress in patients without physical limitations after angioplasty. Delayed thallium-201 imaging and reinjection protocols may be useful to reconcile whether residual ischemia exists in "fixed" perfusion defects. Appropriately timed stress myocardial perfusion imaging 2 to 4 weeks after procedurally successful coronary angioplasty can document improved cardiac functional capacity and reduced ECG and imaging evidence of myocardial ischemia. Although routine serial postangioplasty evaluations cannot be recommended, stress myocardial imaging may be valuable in subjects with defective anginal nociception or extensive myocardium at risk in the area subtended by the angioplasty vessel.

Acute angiographic and clinical results of long balloon percutaneous transluminal coronary angioplasty and adjuvant stenting for long narrowings

Historically, long coronary artery stenoses undergoing percutaneous transluminal coronary angioplasty (PTCA) are reported to have reduced procedural and clinical success in comparison with shorter lesions. The efficacy of long balloons (30 or 40 mm) in long lesions was evaluated. Eighty-two patients had 84 PTCA procedures with a primary long balloon. In all, 86 lesions were available for analysis. Data were collected prospectively on standard PTCA procedure forms. Coronary angiograms were reviewed and measured with digital calipers. Hospital charts were examined for complications. PTCA was performed in the left anterior descending artery in 44 cases (51%), the right coronary artery in 29 (34%) and the circumflex artery in 13 (15%). With the use of a modified classification system, 47 lesions (55%) were class C, 24 (28%) were class B2 and 15 (17%) were class B1. Mean lesion length was 22 +/- 11 mm (range 10 to 72), and 38 lesions (44%) were > or = 20 mm. Twelve patients received an intracoronary stent. The long balloon alone produced angiographic success (< 50% residual stenosis) in 77 lesions (90%). Angiographic success was achieved ultimately in all stenoses, using a stent in 7 patients and a short balloon in 2. There were 2 deaths (2%) and 1 Q-wave myocardial infarction (1%). One patient needed coronary artery bypass surgery. Clinical success without death, Q-wave infarction or bypass surgery was achieved in 83 of 86 procedures (97%). In conclusion, the use of long PTCA balloons with adjuvant stenting produced excellent results in these long stenoses. Lesion length was not a precursor of poor angiographic or clinical outcome.