Utilization of coronary angioplasty and cost of angioplasty disposables in 14 western European countries. European Angioplasty Survey Group

The influence of economic incentives and regulatory factors on the adoption of treatment technologies: a case study of technologies used to treat heart attacks

The Technological Change in Health Care Research Network collected unique patient-level data on three procedures for treatment of heart attack patients (catheterization, coronary artery bypass grafts and percutaneous transluminal coronary angioplasty) for 17 countries over a 15-year period to examine the impact of economic and institutional factors on technology adoption. Specific institutional factors are shown to be important to the uptake of these technologies. Health-care systems characterized as public contract systems and reimbursement systems have higher adoption rates than public-integrated health-care systems. Central control of funding of investments is negatively associated with adoption rates and the impact is of the same magnitude as the overall health-care system classification. GDP per capita also has a strong role in initial adoption. The impact of income and institutional characteristics on the utilization rates of the three procedures diminishes over time.

Physicians' judgments of survival after medical management and mortality risk reduction due to revascularization procedures for patients with coronary artery disease

STUDY OBJECTIVE

s: To assess the accuracy of physicians' judgments of survival probability for medically managed patients with coronary artery disease (CAD), and of the absolute risk reduction of mortality due to coronary artery bypass grafting (CABG) or percutaneous transluminal coronary angioplasty (PTCA) for such patients; and relationships among these judgments and the physicians' propensity to perform revascularization.

DESIGN

Two surveys (for three-vessel or two-vessel CAD) for patients presenting with stable CAD, currently managed medically, and without other life-limiting problems.

SETTING

Multiple educational conferences, 1996-1997.

PARTICIPANTS

Conference attendees.

MEASUREMENTS AND RESULTS

Main outcomes were proportions of patients for whom the physicians would recommend revascularization (CABG for three-vessel CAD, CABG or PTCA for two-vessel CAD), and judgments of the proportions of medically managed patients who would be alive after 5 years, 7 years, and 11 years, and of absolute risk reduction of mortality due to CABG (or PTCA for two-vessel CAD). At least one half of the participants judged the survival rate of medically managed patients with three-vessel or two-vessel CAD to be less than the lowest rates supported by the best available evidence. More than one fourth judged the absolute risk reduction due to CABG to be higher than the highest values based on such evidence. Physicians' propensity to perform revascularization correlated inversely with their judgments of survival given medical management, and with their judgments of absolute risk reduction due to revascularization.

CONCLUSIONS

Physicians may overuse revascularization because of excessive pessimism about survival of medically managed patients, and excessive optimism about the survival benefits of revascularization.

Economic evaluation of enoxaparin sodium versus heparin in unstable angina. A French sub-study of the ESSENCE trial

OBJECTIVES

To perform an evaluation from the societal perspective of the cost of treatment with enoxaparin sodium versus unfractionated heparin (UFH) in patients with unstable angina and non-Q wave myocardial infarction in France.

DESIGN

Four complementary cost-minimisation analyses based on the results of the Efficacy and Safety of Subcutaneous Enoxaparin in Non-Q wave Coronary Events (ESSENCE) international trial were conducted. We assessed differences in medical resource consumption and in duration of hospital stay in the whole study population (n = 3171) and for the French patients (n = 133).

RESULTS

Results were consistent for the study group as a whole and for the French subgroup. Among patients treated with enoxaparin sodium, there was a statistically significant reduction in the use of angiography and percutaneous transluminal coronary angioplasty (whole group study: p = 0.024 and 0.006, respectively) and a trend towards shorter lengths of hospital stay. The differences in angiography and angioplasty rates led to estimated average net cost savings with enoxaparin sodium of French Francs (FF)1555 per treated patient (whole study population) and FF9993 (French subgroup) [1996 values]. The analyses based on the duration of hospital stay resulted in estimated net cost savings with enoxaparin sodium of between FF1014 per treated patient (whole study population) and FF2804 (French subgroup).

CONCLUSION

Our study confirmed earlier results which show that enoxaparin sodium is cost saving in the treatment of unstable angina.

Magnitude and consequences of error in coronary angiography interpretation (the ACRE study)

In the routine reporting of coronary angiograms, there are no contemporary estimates of the magnitude and consequences of interobserver variability. We therefore measured the agreement beyond chance between (1) the number of narrowed arteries on an angiographic report extracted from case notes and independent assessments by 2 cardiologists, and (2) actual patient management over an 18-month follow-up period and each cardiologist's hypothetical management proposal based on abstracted clinical details. Two hundred nine angiograms were randomly selected from 4,121 patients in a prospective study (Appropriateness of Coronary Revascularisation [ACRE study]). The number of narrowed arteries was defined using Coronary Artery Surgery Study (CASS) criteria. For the number of narrowed arteries, cardiologists A and B agreed with the angiographic report in 126 patients (60%, weighted kappa = 0.64) and 124 patients (59%, weighted kappa = 0.63), respectively. In a subset of 92 patients (44%) there was unanimous agreement on the number of narrowed arteries (both cardiologists agreed with the angiographic report). Comparing actual management (34 percutaneous transluminal coronary angioplasty and 39 coronary artery bypass grafting procedures on follow-up) with each of the cardiologist's management recommendations showed agreement in 150 patients (72%, kappa = 0.46) and 154 patients (74%, kappa = 0.48) for cardiologists A and B, respectively. These agreements on management improved (p = 0.05) for cardiologist B (but not A) when analysis was confined to the subset of 92 patients, showing agreement in 73 patients (79%, kappa = 0.60). Thus, in routine clinical practice, the agreement beyond chance in interpretation of the number of narrowed arteries was good. Disagreements on subsequent patient management arose as a result of, and independent of, errors in angiographic interpretation.

Spatial analysis of Percutaneous Transluminal Coronary Angioplasty (PTCA) in Austria

STUDY OBJECTIVES

To investigate the geographical distribution of Percutaneous Transluminal Coronary Angioplasty (PTCA) and morbidity for coronary heart disease, angina pectoris and myocardial infarction by spatial analysis of the standardized morbidity rates (SMR) on district level. To identify clusters by Moran's I Statistic and the Regional Spatial Autocorrelation Coefficient (RSAC) of Munasinghe and Morris. To investigate demand factor morbidity and supply factor health care infrastructure on the district level as reasons for geographical disparity. To describe characteristics of the cluster population and intervention centres.

STUDY DESIGN

Retrospective record linkage study.

SETTING

All hospitals and cardiological centres in Austria (n = 150) which performed the Minimum Basic Data Set (MBDS).

PATIENTS

All Austrian residents who were diagnosed for myocardial infarction, coronary heart disease or angina pectoris in 1995 (n = 87,174).

MEASUREMENTS AND MAIN RESULTS

One 'positive' PTCA cluster (all SMRs > or =0.96) and one 'negative' PTCA cluster (all SMRs < or =0.59) were identified. They differed significantly in morbidity rate, intervention rate and available cardiological beds. The tendency to inverse relation between PTCA utilization and morbidity in the 'negative' cluster supported the thesis of 'inverse care law'. Austrianwide no significant correlation was found between the SMR of PTCA-application and both demand factor and supply factors. Nevertheless, differences between the clusters concerning number and capacity of intervention centres and density of specialists pointed to supply factors as reasons for geographical disparity. The ongoing trend of steady expansion of existing intervention centres and establishment of new ones will reduce the extent of geographical variation in future.

From research to clinical practice: current role of intracoronary physiologically based decision making in the cardiac catheterization laboratory

Decisions regarding coronary interventions should be combined with objective evidence of myocardial ischemia. The most common physiologic approach utilizes hospital facilities outside the catheterization laboratory, requiring additional time and cost. With the introduction of sensor-tipped angioplasty guide wires, distal coronary flow velocity and pressure can be obtained in the cardiac catheterization laboratory, facilitating physiologically based decisions regarding the need for intervention. In the catheterization laboratory, physiologically significant stenoses can be characterized as having impaired post-stenotic coronary flow reserve < 2.0 and pressure-derived fractional flow reserve < 0.75, both variables related strongly to positive ischemic perfusion imaging or stress testing results. Deferring coronary interventions on the basis of normal translesional physiology is safe and is associated with a low rate (< 10%) of lesion progression over a 10-month follow-up period. Preliminary data indicate that excellent physiologic and anatomic end points after balloon angioplasty are associated with low (< 20%) restenosis rates at 6-month follow-up. Clinically relevant relations of in-laboratory physiology support the insight that physiologic, as much as or more than anatomic variables, ultimately determine the functional status of a patient. Current data suggest that an intracoronary physiologic approach complements coronary lumenology and appears to have important clinical and economic implications for patients undergoing invasive evaluation and treatment of coronary artery disease.

The relationship between the supply of cardiac catheterization laboratories, cardiologists and the use of invasive cardiac procedures in northern New England

OBJECTIVES

Utilization rates of coronary angiography and cardiac revascularization have been found to vary between areas. This study addresses the relationship between resource supply and procedure rates.

METHODS

We compared the association of per capita catheterization laboratories, per capita cardiologists and multi-provider markets (where more than one hospital offers coronary angiography services) with the utilization rates for angiography and cardiac revascularization in northern New England, USA. Administrative data were used to capture invasive cardiac procedures. Small area analyses were used to create coronary angiography service areas. Linear regression methods were used to measure associations between the resource supply and utilization rates.

RESULTS

Variation in the use of invasive cardiac procedures was strongly associated with the population-based availability of catheterization facilities and multi-provider markets and unrelated to cardiologist supply or need (as reflected in the hospitalization rates for myocardial infarction). In the multivariate model, an increase of 1 catheterization laboratory per 100,000 population was associated with an increase in the angiography rate of 1.62 per 1000 population; those service areas with multi-provider markets were associated with an additional increase in the angiography rate of 1.27 per 1000 population (R2 = 0.84, P = 0.0006). There was a moderately strong relationship between the catheterization laboratories per capita and the revascularization rates (R2 = 0.43, P = 0.029). Angiography rates were highly associated with cardiac revascularization rates: an increase in the angiography rate of 1 per 1000 population was associated with a 0.46 per 1000 increase in the cardiac revascularization rate (R2 = 0.85, P = 0.0001).

CONCLUSIONS

Our work suggests that current efforts to address variation in cardiac procedures through activities such as appropriateness criteria, guidelines and utilization review are misdirected and should be redirected towards capacity, in this case the supply of catheterization facilities.

EUR-ASSESS Project Subgroup Report on Coverage

The issue of health benefits coverage—and its relation to health technology assessment (HTA)—has gained increasing attention in recent years. Economic constraints on health care, as well as the rapid pace of technological change, have forced European countries to face difficult choices in providing such care. The active use of coverage decision making has been proposed as a tool to help rationalize health care, and HTA has been advocated as a necessary activity to improve coverage decisions.

In-hospital cost of percutaneous coronary revascularization. Critical determinants and implications

BACKGROUND

Hospital charges associated with percutaneous transluminal coronary revascularization (PTCR) in the United States exceeded $6 billion in 1994 and are likely to be constrained in some manner in the near future. Despite this high cost to the public, little is known about the major determinants and sources of variability of PTCR.

METHODS AND RESULTS

From a consecutive series of 1258 procedures with attempted PTCR at a single tertiary referral center, we analyzed 65 clinical, angiographic, physician, and outcome variables as potential correlates of total (hospital and physician) cost. Direct and indirect costs, both hospital and physician, were determined on the basis of resource utilization using "top-down" methodology and were available for 1237 procedures (1086 patients) (98.3%). Mean (+/- SD) patient age was 62 +/- 11 years, 76% were male, 3% had acute myocardial infarction, 71% had unstable angina, 58% had multivessel disease, left ventricular ejection fraction was 54 +/- 12%, 26% had use of at least one nonballoon revascularization device, and median length of stay was 4.4 days. Procedural success was obtained in 89%, and major complications (death, bypass surgery, or Q-wave myocardial infarction) occurred in 3.8%. The median cost was $9176, but it was asymmetrically distributed, and the interquartile and total ranges were wide ($7333 to $13,845 and $3422 to $193,474, respectively). Analyses of independent correlates of cost and loge(cost) were performed using multivariate linear regression in training and test populations. Modeling found 15 independent preprocedural correlates of loge(cost) (R2 = .37) and 23 overall correlates (R2 = .65), excluding length of stay per se. Additional of length of stay to the model increased the explanatory power of the model to R2 = .82. Preprocedural variables most predictive of loge(cost) included presentation with acute myocardial infarction, decision delay (> 48 hours between admission and diagnostic angiography and/or > 24 hours between angiography and intervention), weekend delay, use of intra-aortic balloon counterpulsation, intention to stent, creatinine > or = 2.0 mg%, and lesion complexity (modified American College of Cardiology/American Heart Association score) (all P < .001). In the model that included postprocedural variables as well, length of stay, noncardiac death, urgent bypass surgery, use of the Rotablator, Q-wave myocardial infarction, rise in creatinine > or = 1.0%, and blood product transfusion were all strong independent correlates of loge(cost) (P < .001).

CONCLUSIONS

The range of total hospital costs associated with percutaneous intervention is extraordinarily wide. Baseline patient characteristics account for nearly half of the explained variance, but procedural complications and system delays account for much of the remainder. Quantification of the determinants of cost may promote more economically efficient care in the future.

The invasive management of angina: issues for consumers and commissioners

OBJECTIVE

To review, from the purchaser's perspective, the current state of knowledge of techniques for investigation and treating coronary artery disease. The study was based on evidence from past and continuing randomised controlled trials (RCTs). CRITERIA FOR INCLUSION OF REPORTS: Articles listed on Medline (1990-3) with the keywords coronary disease, angina, and unstable angina (combined with surgery, economics, therapy, or drug therapy) and percutaneous transluminal coronary angioplasty (PTCA) and coronary artery bypass grafting (CABG) were included. Articles published before 1990 were obtained from two comprehensive literature reviews published by the Rand organisation in 1991 and from the papers obtained using the Medline search. A hand search of relevant journals published between July 1993 and June 1994 was also undertaken. Results from more recently published RCTs are included.

RESULTS

CABG provides improved angina relief compared with drug treatment and may prolong life in patients with more severe illness. PTCA is also better than drug treatment, but less so than CABG, and its cost advantages over CABG decrease with time. Repeat intervention for return of symptoms is more frequently required after PTCA, but increasing numbers of patients are also undergoing second and third repeat CABG for graft occlusion in the years after the original operation. Newer PTCA techniques are not, as yet, fully evaluated. One technique, atherectomy, has been shown to be no more effective, and more expensive, than conventional balloon angioplasty. In the short term intracoronary stents reduce the problems associated with vessel occlusion after PTCA and therefore reduce the need for further intervention. PTCA should not be performed without ready access to cardiothoracic support. There is an increasing trend towards the development of coronary catheterisation units at peripheral sites. This may lead to increasing, inappropriate use of this investigation in suboptimal circumstances.

CONCLUSIONS

Ischaemic heart disease is an important cause of morbidity and mortality and invasive management techniques are developing rapidly; some service expansion is occurring without trial evidence. More research is required to determine the optimum balance of PTCA, CABG, and angiography and population requirements for these procedures. In the meantime, in the absence of firm long term evidence of the superior cost effectiveness of PTCA compared with CABG, the rapid expansion of this procedure should be limited. Patients should be fully informed of the benefits and disadvantages of CABG and PTCA, where either procedure is indicated, to enable them to make fully informed choices.

Coronary revascularisation: why do rates vary geographically in the UK?

OBJECTIVE

To explain the reasons for geographical variation in the use of coronary revascularisation in the United Kingdom.

DESIGN

This was a cross sectional ecological study.

SETTING

NHS and independent hospitals performing coronary revascularisation for the 11.6 million residents of the south east Thames, East Anglian and north western health regions in England plus Greater Glasgow, Lanarkshire, Ayr and Arran health boards in Scotland were included.

SUBJECTS

All residents aged > or = 25 years in 1992-93 who underwent coronary artery bypass grafting (CABG) or percutaneous transluminal coronary angioplasty (PTCA) in either the public or private sector were included.

MAIN MEASURES

Crude and age-sex standardised intervention rates for residents of the 42 constituent districts and boards were determined. Variation was measured using the systematic component of variation.

RESULTS

Considerable systematic variations in district rates of CABG and PTCA existed. These variations mostly arose from differences in supply factors. Higher rate districts were characterised by being close to a regional revascularisation centre and having a local cardiologist. Demand factors such as the level of need in the population (measured by coronary heart disease mortality) and the lack of use of alternative treatments not only failed to explain the observed variation but were inversely associated with the rate of intervention--an example of the inverse care law. The finding that the residents of more socially deprived districts experienced higher intervention rates was probably subject to confounding due to their close proximity to specialist centres.

CONCLUSIONS

If greater geographical equity of use for the same level of need is to be achieved, attention must be paid to the supply factors that determine levels of utilisation. As responsibility for purchasing these procedures is decentralised, utilisation might become even more unequal.

Transoesophageal echocardiography as the sole diagnostic investigation in patients with suspected thoracic aortic dissection

OBJECTIVES

To assess the value and limitations of using transoesophageal echocardiography as the sole diagnostic test in patients with suspected thoracic aortic dissection.

DESIGN

Retrospective data review over a two year period.

SETTING

A regional cardiothoracic centre.

PATIENTS

Data were compiled from admission records, surgical records, and lists of patients undergoing diagnostic investigations in the hospital. Patient's notes were used to identify presentation, management, and outcome.

INTERVENTIONS

Patients were managed according to the policy of our unit, which is to treat patients with dissection affecting the ascending aorta by an operation. Patients with uncomplicated dissection sparing the ascending aorta are initially managed medically.

MAIN OUTCOME MEASURES

In hospital and two year follow-up of patients who were investigated by transoesophageal echocardiography alone.

RESULTS

Of 48 patients referred, 45 underwent transoesophageal echocardiography. Dissection was confirmed in 22 patients. Transoesophageal echocardiography showed the proximal extent of the dissection in 21/22 (96%) and only one patient required a further diagnostic investigation. Ten patients with dissection of the ascending aorta underwent graft replacement of the ascending aorta; operative mortality was 10% and their two year survival was 80%. Of the eight patients with dissection of the descending aorta, six were discharged home, and five were alive at two years. No patient without evidence of dissection on their initial transoesophageal echocardiographic examination required re-investigation into possible dissection in the two years after discharge.

CONCLUSIONS

In patients with suspected thoracic dissection transoesophageal echocardiography rapidly and safely gives all the necessary diagnostic information. Further investigations, including coronary angiography, before surgery are unnecessary.

Trends in the age and sex of patients undergoing coronary revascularisation in the United Kingdom 1987-93

OBJECTIVES

To describe how coronary revascularisation rates in the United Kingdom (in the public and private sectors) vary by age and sex; how these relations have changed between 1987 and 1993; whether significant differences exist between geographical areas, public and private sectors, and hospitals; and to make comparisons with trends in North America.

DESIGNS

Secondary analysis of data on the age, sex, procedure, NHS/private, and health district of residence of patients.

SETTING

Resident population of South East Thames, East Anglian, and North Western health regions and Greater Glasgow, Lanarkshire, and Ayr/Arran health boards (11.6 million; 20% United Kingdom population).

PATIENTS

All 19,665 residents who underwent either coronary artery bypass grafting or percutaneous coronary angioplasty without any concomitant procedure during 1987-8, 1989-90, 1991-2 and 1992-3 in either NHS or independent hospitals.

MAIN MEASURES

Population based rates of revascularisation by age, sex, area of residence, and NHS/private treatment. Secular trends in the age (mean, standard deviation, range), and sex ratio (male to female) of patients.

RESULTS

Revascularisation rates in men were about four times higher than in women (1992-3: 1340 v 362/10(6) aged 25 years or more). The highest rates were in those aged 55-64 years (for men) and 55-64 and 65-74 years (for women). In 1992-3 the mean age of female patients was three years older than that for men (61.2 v 58.3) and that for coronary artery grafting was over two years older than for angioplasty (59.4 v 56.9). Between 1987-8 and 1992-3 the male to female ratio decreased (4.2:1 to 3.55:1) and the mean age of patients increased steadily by about six months each year. Intervention rates for the older groups increased faster than those for the younger, particularly in high rate regions. The age and sex mix of patients varied between regions and districts/boards. The mean age of patients varied by nine years and the sex ratio varied twofold between NHS hospitals. The male to female ratio was higher in private than NHS patients (1992-3: 5.5:1 v 3.6:1), suggesting greater access to care for men than women in the private sector. The trends observed in the United Kingdom are similar to those that have occurred in North America, with the exception of a decrease in the male to female ratio, which has not previously been reported.

CONCLUSION

The increase in the revascularisation rate has been accompanied by an increasing proportion of women and older people. The extent of these changes varies between geographical areas. The change in the sex ratio has occurred despite an increasing contribution by the private sector, to which women have less access than men.

Evaluation of the systematic use of a new type of diagnostic/interventional 6F catheters for coronary angiography and angioplasty

Coronary angioplasty performed immediately after coronary angiography has raised interest to develop diagnostic catheters potentially usable for interventions (i.e. Diaventional catheters). To evaluate the performance and cost-effectiveness of such material, we performed a prospective study in 100 consecutive patients with a > 50% pre-angiographic likelihood of coronary angioplasty in 85 of them. Angioplasty was actually performed in 61 patients. Of the 56 (92%) immediate angioplasty procedures, 33 (59%) were performed successfully with the Diaventional catheter chosen initially. In 23 cases, another guiding catheter was used for technical failure (2 cases) or because of operator's choice (21 cases). Angiographic success of angioplasty procedures was 97% with Diaventional and 91% with "standard" guiding catheters. Based on current market prices, the costs of the systematic use of such diagnostic/interventional catheters were 11% less than the projected costs of the standard strategy. Thus, this new type of catheter is both safe and cost-effective for the majority of coronary angioplasty procedures "at first sight." It could become a logical first choice for diagnostic coronary angiography, when the likelihood of immediate subsequent angioplasty is high and at relatively low risk.