[Too many heart catheter procedures in Germany ?]. / Zu viele Herzkatheteruntersuchungen in Deutschland?

BACKGROUND AND OBJECTIVE: Absolute numbers of cardiovascular procedures are higher in Germany as compared to other European countries. This fact is used as an argument for overuse. Therefore other indicators of an inappropriate use of these resources should be of interest. PATIENTS AND METHODS: The relationship between diagnostic cardiac catheterisations and consequent revascularisation procedures were compared in 8 European countries. In addition the indication criteria for cardiac catheterisations were reviewed in a German registry of 205.581 consecutive inpatients. RESULTS: Revascularisation procedures after diagnostic catheterisations in 8 countries range from 39,1 % to 57,9 %. Germany reaches 43,2 %. A relation between absolute numbers of diagnostic and percent subsequent revascularisation procedures does not exist. In a German registry the following indications for cardiac catheterisation could be identified: Acute Coronary Syndrome 22,9 %. Angina pectoris according to the Canadian Cardiac Society classification was present: CCS II/III in 80,3 %, CCS IV in 17,2 %. An exercise test was performed in 43 %. Final diagnoses were: significant coronary disease 69,5 %, exclusion of disease 9,4 %, lesions < 50 % 9 %, other cardiac disease 12,1 %. CONCLUSION: Absolute numbers cannot be used as an indicator of overuse of cardiovascular procedures. Instead standards for data acquisition should be established on European, national and regional levels. In addition a validation procedure for criteria has to be developed in order to judge the appropriateness of indications for invasive cardiac procedures in different health care systems.

Volumetric analysis of the right and left ventricle in a porcine heart model: comparison of three-dimensional echocardiography, magnetic resonance imaging and angiocardiography.

UNLABELLED: Three-dimensional echocardiography and magnetic resonance imaging allow the volumetric analysis of ventricular volumes independent of geometric assumptions. The aim of the study was to compare these methods and the common angiocardiography in a cardiac model of known volume. METHODS/MATERIALS: Right and left ventricular (RV, LV-) volumes were measured in a specific animal model directly ('true volume') and with different imaging techniques. Three-dimensional echocardiography (3D-Echo) and magnetic resonance imaging (MRI), both of which permit a volume estimation without necessitating geometric assumptions, and angiocardiographic volumetry which is based on the Simpson rule were used in this study. RESULTS: The best results were achieved with MRI (RV: r(2)=0.99, mean difference: -1. 9+/-3.3%; LV: difference r(2)=0.99,: 2.9+/-5.0%). Likewise, 3D-Echo showed a very good correlation with the true volumes (RV: r(2)=0.93, difference: 9.3+/-6.3%; LV r(2)=0.96, difference: 4.8+/-9.9%). The greatest deviations were observed during angiocardiographic volumetry (LV: r(2)=0.98; difference: 14.4+/-9.2%), particularly when measuring the right ventricle (RV: r(2)=0.82, difference: 57. 9+/-40.1%). Consequently, the direct comparison between 3D-Echo and the other methods yielded the best correspondence with MRI (RV: Bias: 3.7 ml, limits of agreement: 7.7 ml; LV: Bias: 3.7 ml, limits of agreement: 4.9 ml). In contrast, the differences between 3D-Echo and angiocardiography were marked (RV: Bias: 25.5 ml, limits of agreement: 11.1 ml; LV: Bias: 8.7 ml, limits of agreement: 13.2 ml). CONCLUSION: In a porcine cardiac model, 3D-Echo permits a relatively precise measurement of ventricular volumes with a slight under-estimation. MRI yielded the most precise volumetry, and the correlation between 3D-Echo and MRI was quite good. Particularly for the right ventricle, the angiocardiographic measurement was attached with the greatest error and thus appears ill-suited for the volumetry of geometrically more complex ventricles.

[First annual report of practitioners of interventional cardiology in private practice in Germany. Results of procedures of left heart catheterization and coronary interventions in the year 1996]. / Erster Jahresbericht niedergelassener Invasivkardiologen in Deutschland. Ergebnisse für diagnostische Linksherzkatheteruntersuchungen und Koronarinterventionen 1996.

The German Society for Cardiac Angiography and Interventions in Private Practice has started a registry of cardiac procedures since 1996 in order to establish a standard for performance. Although quality management for the cath lab makes sense and is also legally required, there is no generally recommended infrastructure for quality assurance existing in Germany at this time. Therefore, the German Society of Cardiologists in Private Practice (BNK) initiated a project in 1994 to develop a computer program for paperless documentation of diagnostic cardiac catheterizations and coronary interventions (PTCA) using a minimal data set. In 1996, 8 private associated groups participated in this project. The (anonymous) analysis of 10,316 diagnostic cardiac catheterizations and 2597 PTCA yielded the following results: In 95% of the patients, diagnostic cardiac catheterization was performed using the femoral and in 5% the brachial/radial approach. The mean volume of administered contrast medium was 164 +/- 138 ml/patient. The mean LV-EF was greater than 50% in 58.4% of the patients and between 30% and 50% in 10.1%. Coronary artery disease was diagnosed in 69.6% of the patients and valvular/congenital heart disease in 8.5%. In 18.4% of the patients undergoing diagnostic cardiac catheterizations no significant heart disease was identified. Mortality in the cath lab as well as the rate of cerebral insults was 0.05%. In 22.9% and 19% of the patients PTCA and cardiac surgery respectively was recommended. In patients undergoing PTCA, stable angina was present in 74.4% and unstable angina in 13.1%. Of the total number of PTCA procedures, 5.8% were performed in the setting of acute myocardial infarction. The PTCA lesion success rate was 96%, the mean diameter stenosis was 81% pre and 6% post-intervention. The mortality rate at 1 month post-PTCA was 0.4%, and myocardial infarction 1.0%. An acute occlusion occurred in 1.3% of the PTCA patients; 0.6% had to be transferred for emergency bypass surgery. None of the cath labs had on-site surgery. In comparison to other registries, our data show some similarities but also some different trends. Thus, our newly developed software proved to be reliable, fast and easy to use. Participating centers receive immediate feedback regarding their position within the whole group.

The role of radionuclide angiocardiography in the treatment of patients receiving doxorubicin-based chemotherapy: a reassessment.

We attempted to evaluate the role of radionuclide angiography in the routine treatment of patients receiving doxorubicin-based therapy in a university hospital setting. We identified 222 cancer patients treated with doxorubicin or who underwent radionuclide angiography with the intent to receive doxorubicin at the University of Iowa in 1989. We examined the cumulative doses of doxorubicin, results of radionuclide angiograms, cardiac risk factors, and clinical outcomes and survival of patients. Of 222 patients, 168 (76%) underwent at least one radionuclide angiogram and received doxorubicin. Only a baseline study was performed in 136 (81%) of these 168 patients. Only 32 underwent follow-up study during therapy; six patients discontinued therapy for an 11-21% decrease in left ventricular function. The mean dose of doxorubicin received was 211 mg/m2, and 193 patients (96%) received a cumulative dose <450 mg/m2. Only two patients (1%) had heart failure. A questionnaire sent to medical oncologists in Iowa showed that use of radionuclide angiography in our institution reflected practice throughout the state. The majority of patients in our population who underwent radionuclide angiography had a single baseline study, which provides little clinically useful information. The majority of patients receiving doxorubicin as currently employed can be safely treated without radionuclide angiography.

Outcome of bypass surgery in patients with chronic ischemic left ventricular dysfunction. Predictive value of MR imaging.

PURPOSE: To determine the preoperative findings of MR imaging of the left ventricle (LV) that could best predict the functional outcome of the LV after surgical revascularization. MATERIAL AND METHODS: Patients with angina pectoris, previous myocardial infarction, and dysfunction of the LV, and who had a preoperative cine MR, were re-evaluated after bypass surgery with MR in a study on the effects of revascularization after mean 22 months. RESULTS: Angina pectoris was relieved in all patients except one, but the maximum workload during the exercise test was increased in only 3 patients. Coronary angiography showed that 37 of 45 (82%) of the distal anastomoses were open. The LV ejection fraction was the same before and after operation both at angiography and MR imaging. MR showed LV end-diastolic volume to be increased from 190 +/- 50 ml to 250 +/- 70 ml. Compared to angiography, MR provided additional information regarding myocardial wall thickness and function, and the size of myocardial infarction. Improvement in systolic wall thickening was seen in 65% of the segments that had had an end-diastolic wall thickness (EDWT) greater than 15 mm before operation, while only 4% of the segments with EDWT < 6 mm improved. In the wall thickness range of 6-15 mm, MR was unable to predict the functional outcome of the LV. CONCLUSION: Preoperative MR findings of thick myocardial walls with poor function seem predictive of improved function after revascularization. When the LV wall thickness is less than 6 mm, no improvement should be expected.

Angiographic determination of left and right ventricular volumes and left ventricular mass in normal infants and children.

Left and right ventricular (LV and RV) volumes and LV mass were assessed by angiography in 63 infants and children without major cardiovascular abnormalities. LV and RV end-diastolic volumes (EDV) were excellently expressed as a function of body surface area (BSA) with an exponential equation: LVEDV = 83.7 (BSA)1.29 ml (r = 0.96, p < 0.001), RVEDV = 87.9 (BSA)1.29 ml (r = 0.94, p < 0.001). LV ejection fraction (EF) averaged 64 +/- 6 (mean +/- standard deviation) %, and RVEF 56 +/- 5%, each of which was independent of BSA. LV mass was well expressed as a function of BSA with an exponential equation: LV mass = 75.4 (BSA)1.22 g (r = 0.86, p < 0.001). LV mass/LVEDV was constant, and averaged 0.96 +/- 0.22 g/ml. Thus, the values of LVEDV, RVEDV, and LV mass in infants and children with various heart diseases may be estimated with reasonable accuracy as a percentage of normal values predicted from their BSA by using the above-proposed exponential equations. The normal values of LVEF, RVEF and LV mass/LVEDV themselves can be compared with these parameters in pediatric patients with heart diseases because of their independence of BSA.

Analytic isocenter calibration. A new approach for accurate x-ray gantries.

Isocenter calibration transforms cardiac structures in digitized biplane angiograms to absolute dimensions, calculating their radiological magnification and video transformation. Since a scaling device is not required, isocenter calibration yields to more accurate measurements than the widely used reference object calibration. Both isocenter methods reported so far, regarding geometrically inaccurate x-ray gantries, yield to different and complex computational formulas. Since these formulas are hard to understand, isocenter calibration is less widely used. To facilitate the implementation of the isocenter calibration, the basic formulas for accurate x-ray gantries are derived. Shifting virtually one x-ray system onto the other, basic isocenter calibration is derived geometrically in three simple steps. The radiological magnification of an object is illustrated as a ratio of planes. The calculation of all parameters entering the computations is demonstrated geometrically, by use of the isocenter of the x-ray gantry. The derivation gives a clear idea of isocenter calibration. It is simple to derive and facilitates the understanding of the error regarding developments. When geometrical inaccuracies vanish, all formulas become equivalent. However, even if the inaccuracies increase, all methods provide nearly identical results, indicating the robustness of isocenter calibration.

[A new method for calculating the mass of the left ventricle by angiocardiography]. / Una nuova metodica per il calcolo della massa del ventricolo sinistro mediante angiocardiografia.

The authors describe a simplified method to determine left ventricular volume and mass from the ventricular silhouette, taken from a right oblique anterior angiographic projection at 30 degrees, used to measure the telediastolic surface and major axis, and of measuring the telediastolic thickness of the ventricular wall in the postero-lateral segment of the silhouette taken from a left oblique anterior angiographic projection at 60 degrees. Sixty-four ventricular silhouettes were analysed in patients undergoing left kineventriculography for coronaropathy and ventricular mass was determined using both the new and traditional methods. Using the new method mass values (mean value 87.85 g/sq.mt. and SD 34.04) were obtained which were significantly correlated (r = 0.999) with values obtained using the standard method (mean value 88.02 g/sq mt and SD 34.11). The practical advantages of the new method are discussed (simplicity of calculating equation without determining the minor axis of the ventricular silhouette), together with its limits due to the monoplanar technique used to calculate the volume and the measurement of wall thickness in those cases in which the postero-lateral wall is considered the most representative of the mean thicknesses of the left ventricular wall. Lastly, the paper discusses the possibility of applying this method to non-invasive procedures, such as the two dimensional echocardiogram, where more reliable mass values could be obtained even in the event of non-uniform wall thickness.

Iopamidol in cardioangiography: a retrospective, multicenter study. Part I. Adult patients.

To evaluate the occurrence of complications during diagnostic or interventional catheterization a retrospective analysis of catheterization procedures in 12 Italian laboratories using the nonionic contrast medium (CM) iopamidol (370 mgI/ml) was performed. Data obtained on 26,219 patients greater than or equal to 14 years are presented. The overall complication rate was 1.89% (485/26,219). The overall mortality rate was 0.1% (27/26,219). Procedure related complications were 389 (1.48%) and CM related complications were 106 (0.4%). No death was attributed to CM. Ventricular fibrillation (VF) rate was 0.11% comparable to the low rate observed with nonionic CM in other studies and less than the rate observed in surveys concerning the use of ionic CM. Fifty-seven thrombotic events were recorded (0.22%), a rate comparable with other surveys with ionic and nonionic CM. The total complication rate (6.1%), the rates of coronary occlusion (1.34%), myocardial infarction (0.37%) and urgent coronary artery by-pass grafting (0.5%) in 1,348 coronary angioplasties were lower than those recorded in previous surveys. These data confirm a good tolerability and no increased risk of VF and thrombotic events with iopamidol in cardiac catheterization.

Iopamidol in cardioangiography: a retrospective, multicentre study. Part II. Paediatric patients.

To evaluate the complication rate in paediatric cardioangiography with the nonionic contrast medium iopamidol data on 8,166 procedures were retrospectively collected in 12 centres. The overall complication rate was 3.78% (309/8,166). 3.44% were related to the procedure, and 0.34% to the contrast medium. The mortality rate varied with age. It was higher in patients less than 2 months (0.38%) than in patients greater than 2 months-2 years (0.06%) and in patients older than 2 years (0.03%). The total complication rate was higher than the one observed in a similar retrospective analysis performed in adult patients (1.89%). This difference is probably due to higher risk conditions of the younger patients. However the contrast medium related complication rate (0.34% vs 0.4%) and the mortality rate (0.11% vs 0.1%) were comparable, confirming the good tolerability of iopamidol in cardiac catheterisation also in paediatric patients.

[Coronary angiography, percutaneous transluminal coronary angioplasty and coronary surgery, valvular interventions and anti-arrhythmia agents and fibrinolysis for acute myocardial infarction in Switzerland]. / Coronarographie, angioplastie percutanée transluminale coronaire et chirurgie coronaire, interventions valvulaires et anti-arythmiques et fibrinolyses pour infarctus aigu du myocarde en Suisse.

Besides the description of the activities of the Working Group PTCA and Fibrinolysis of the Swiss Society of Cardiology, number and distribution of coronary angiograms and angioplasties (PTCA) and aortocoronary bypass operations performed in 13 Swiss centers during 1989 are presented and commented. It is of note that the number of PTCA procedures has increased further during the last year, whereas the number of bypass operations stayed fairly constant over the last three years. PTCA is done today almost as frequently as coronary artery bypass surgery in Switzerland. There are, however, marked differences between individual centers: the number of PTCA procedures in relation to coronary angiograms varies between 5% and over 40%. A large part of these interventions is performed at private hospitals. More than 85% of the PTCA procedures were single vessel procedures. Catheter interventions on heart valves and on the conductive system were done almost exclusively at University Hospitals. The 1989 survey of the treatment of acute myocardial infarction with fibrinolysis covers only hospitals with catheterization laboratories and is therefore not entirely representative for the total activity in Switzerland. Almost 20% (0-80%) of all patients admitted for acute myocardial infarction received fibrinolysis with important differences between individual centers.

Do cardiologists have higher thresholds for recommending coronary arteriography than family physicians?

The purpose of this study was to use a new model of decision making to understand variability in physicians' utilization of diagnostic tests. We studied physicians' recommendations for coronary arteriography in hypothetical patients with chest pain by analyzing responses of 235 cardiologists and family physicians. Thresholds for testing were derived by obtaining estimates of the probability of disease and recommendations for coronary arteriography before and after an exercise test. We found that cardiologists compared with family practitioners had a significantly higher decision threshold and recommended coronary arteriography in fewer patients. These findings suggest that analyzing physicians' decision-making thresholds may be used to characterize differences in the practice behavior of groups of physicians.

How coronary angiography is used. Clinical determinants of appropriateness.

Using ratings of appropriateness derived from an expert physician panel, we measured how appropriately physicians in 1981 performed coronary angiography in a randomly selected, community-based sample of cases in the Medicare population. We studied large geographic areas (three sites) in three states, representing regions of high and low use. The high-use site had fewer procedures classified as appropriate (72%) than either low-use site (77% and 81%, respectively). Over all sites, 17% of procedures were classified as inappropriate. Patients in the high-use site were older, had less severe angina, and were less intensively medically treated than patients in either of the low-use sites. Patients without angina who had not undergone exercise testing constituted the most common subgroup of inappropriate cases. Although overall differences in appropriateness were not large, practice differences do exist. This analysis of practice differences among study sites provides the clinical basis for understanding the small, but significant, differences in the appropriateness of use of coronary angiography. The finding of 17% inappropriate use may be cause for concern.

The appropriateness of using a medical procedure. Is information in the medical record valid?

Understanding the clinical appropriateness of a procedure's use may be critical in explaining geographic variations in its use. Little is known, however, about whether data on appropriateness can be obtained from a medical record. A national panel of physicians formulated a list of 300 mutually exclusive, detailed clinical indications for performing coronary angiography. Using this list, we compared the reasons physicians perform coronary angiography as revealed in medical records with those given in interviews with the physicians who actually did the procedure. Thirty-five of 47 eligible billing entities (74%) from two Los Angeles Professional Standards Review Organization areas participated. These physicians practiced in 14 hospitals and accounted for 81% of all angiographies performed on Medicare patients in the two areas. Sixty-six records (approximately two per physician) were reviewed; physician interviews were conducted by two trained data collectors who were blinded to each other's results. Ninety-one percent agreement was reached on the specific indication for performing coronary angiography when information from the record review and interview was compared. We conclude that medical records yield valid information on why coronary angiography is performed and that they are a suitable source to use in judging the appropriateness of that use.