A prognostic computer model to predict individual outcome in interventional cardiology. The INTERVENT Project

It is not yet possible to predict an individual's outcome from percutaneous transluminal coronary angioplasty or alternative/adjunctive coronary interventional techniques. The purpose of the INTERVENT project is to redefine complications associated with coronary interventions, to set up a prognostic computer model to predict individual outcome and to compare the results to those of conventional statistical techniques. 2500 data items were analysed in 455 consecutive patients (mean age: 61.1 +/- 8.3 years; range 33-84 years; 80.4% male, 16.7% unstable angina, 5.1%/10.1% acute/subacute myocardial infarction) undergoing coronary interventions at three university centres. In-lab/out-of-lab complication rates were 0.4%/0.9% (death), 1.8%/0.2% (abrupt vessel closure with myocardial infarction) and 5.5%/4.0% (haemodynamic complications). Computer algorithms derived by applying techniques from artificial intelligence were able (1) to reduce the set of possible relevant risk factors from 2500 to about 40, (2) to predict individual risk with an accuracy of > 95% and (3) to explain the structural relationship between outcome and risk factors. Patient data from two centres were used to construct and test the algorithm. Data from a third centre were used to evaluate the algorithm. The most important predictors-were acute myocardial infarction, heart failure (NYHA class > II), unstable angina, complex lesions, high low density lipoprotein cholesterol and duration of coronary heart disease. Neither age nor gender impaired the percutaneous transluminal coronary angioplasty results in acute ischaemic syndromes; however, for stable angina, procedural risk increased with age. There was little risk from primary percutaneous transluminal coronary angioplasty in acute myocardial infarction in patients with NYHA heart failure classes I-II; however, the risk was high for patients in NYHA classes > II, either with or without additional thrombolysis. Alternative/adjunctive intervention techniques were no predictors for in-lab-, but were predictors for post-procedural complications.

Dipyridamole scintigraphy and intravascular ultrasound after successful coronary intervention

Despite angiographically successful interventions, perfusion defects are not uncommonly observed in postinterventional perfusion scintigrams. The aim of this study was to test the hypothesis that perfusion defects after coronary intervention are associated with a significant residual stenosis in the treated vessel segment detectable by intravascular ultrasound but not by angiography.

METHODS

Forty consecutive patients with angiographically successful coronary interventions were prospectively studied by intravascular ultrasound immediately after the intervention. Within 48 hr after the intervention all patients had myocardial scintigraphy using 99mTc-methoxyisobutyl-isonitrile SPECT after dipyridamole stress. Myocardial perfusion defects in the scintigram were assigned to a segmental left ventricular model and compared to the perfusion territory of the treated vessel estimated from the coronary angiogram.

RESULTS

Twenty of 40 patients had reversible myocardial perfusion defects. Mean ultrasound area stenosis was 50% in these patients and 33% in patients without perfusion defects (p < 0.002); ultrasound percent plaque area was 75% versus 63% (p < 0.0001), respectively. The best concordance between residual area stenosis and perfusion defects was found for an ultrasound area stenosis > or = 40%.

CONCLUSION

Patients with stress-induced myocardial perfusion defects immediately after successful coronary intervention show high-grade residual stenoses that are more pronounced in patients with perfusion defects than in patients with normal postinterventional scintigrams. In addition, vessels serving myocardial regions with perfusion defects showed a significantly higher plaque burden indicating diffuse atherosclerotic changes in the vessel. The evaluation of the postprocedural result by intravascular ultrasound contributes to a better understanding of the discrepancy between the angiographic finding of a widely patent vessel but scintigraphic evidence of impaired perfusion.

[Prescribing practice for beta blockers at patient discharge to ambulatory care. A health care economic evaluation in a cardiology patient sample with special reference to drug budgeting]

Beta blockers are known to reduce mortality from hypertension and coronary heart disease after myocardial infarction. Recent health care laws in Germany did impose a medication budget for ambulatory patients only. To evaluate the effects of this administrative instrument we studied prescribing practices of beta blockers in patients transferred from inpatient to ambulatory care. Specifically, we aimed of assessing the quality and cost effectiveness of beta blocker prescriptions. In a prospective cohort study of 142 patients discharged from a tertiary care center, the beta blocker medication was continued in 130 patients (91%). Adequate quality of the medication, defined as continuation of a beta blocker in sufficient dosage, was found in 77% of patients. Cost effective prescribing practices, defined as adequate quality at a lower cost than at discharge, were documented in 10% of the patients. However, inadequate dosage or even omitting of a beta blocker was found in 23% of patients. Overall, we found high-quality prescribing practices in more than two-thirds of our patients, but documented inadequate care in more than 20%. Our study did not document any consistent pattern between medication changes and cost-effective prescribing practices attributable to medication budgeting in Germany.

[Intracoronary ultrasound changes the therapeutic approach in ambivalent angiography findings]

Despite careful evaluation of multiple projections, coronary angiography may give ambiguous results of lesion severity. The purpose of this study was to analyze the impact of ultrasound imaging on revascularization treatment strategy in angiographically ambiguous findings. We reviewed our experience with such equivocal angiographic findings before intervention in 31 patients (34 lesions) who had additional intravascular ultrasound (IVUS) to clarify coronary anatomy. Intervention was felt to be indicated if area stenosis by IVUS exceeded 50% in the left main or 75% in other major coronary arteries. To evaluate the clinical efficacy of IVUS based management strategies, all patients had clinical follow-up after 1 year. Seven of nine ostial lesions were overestimated by angiography, but two of three left main lesions were found to be significant. Seven lesions in one of the proximal coronary arteries whose significance was difficult to judge by angiography were found not to be significant by IVUS, whereas in the other four severe obstruction was confirmed. Membranes by angiography corresponded to remnants of ruptured plaques by IVUS in all five patients. However, significant narrowing was found in only two patients. Side branch ostial lesions were ruled out by IVUS in all four instances. Two patients with unstable angina but normal angiograms showed complex atherosclerotic plaques in the left coronary artery. IVUS led to a change of therapy in 21 patients (revascularization instead of conservative treatment in two and cancellation of initially intended intervention in 19). At follow-up examination, 17 of these 21 patients were free of cardiac symptoms. Interventions at the site thought not severely diseased by IVUS had to be performed in two patients with persistent angina who were afterwards free of symptoms. One patient with persistent chest pain had a second coronary angiogram during the follow-up period, but conservative therapy was continued. Evaluation was impossible in one patient because of bypass surgery due to another coronary lesion. In conclusion, IVUS was clinically useful in patients with angiographically ambiguous findings and resulted in a change of therapy in 21/31 patients obviating interventions in 19 patients with excellent clinical results.

Coronary plaque morphology affects stent deployment: assessment by intracoronary ultrasound

The purpose of this study was to evaluate the changes in arterial wall morphology induced by coronary stent implantation and the influence of plaque morphology on stent expansion by intravascular ultrasound. Intravascular ultrasound imaging was performed in 25 lesions before and after Palmaz-Schatz stent implantation. In the 25 lesions with ultrasound images before and after stent deployment angiographic percent diameter stenosis decreased from 71% +/- 11% to 6% +/- 14%. By ultrasound there was a gain in luminal area from 2.0 mm2 +/- 1.5 mm2 to 6.6 mm2 +/- 2.1 mm2 owing to gain in external elastic membrane area of 2.5 mm2 +/- 1.7 mm2 and reduction of plaque area of 2.1 mm2 +/- 1.7 mm2. Calcified lesions (n = 8) showed significantly less relative luminal gain (218% +/- 128% vs. 421% +/- 276%, P = .01), and stent expansion was significantly less symmetric (minimal/maximal stent diameter 0.8 +/- 0.1 vs. 0.9 +/- 0.1, P = .002) as compared to non-calcified lesions (n = 17). The difference in lumen area within the stent between the previously stenotic area and the ends of the stent was significantly larger in calcified lesions as compared to non-calcified lesions (29 +/- 28% vs. 8 +/- 23%, P = .03). Both vessel stretch and plaque reduction contribute to the luminal gain after coronary stenting. Calcified lesions interfere with optimal stent expansion.

[Lumen enlargement in coronary angioplasty: qualitative and quantitative analysis of vascular mechanisms with intravascular ultrasound]

The purpose of this study was to determine the mechanisms by which balloon angioplasty increases luminal patency. Therefore serial examinations with intravascular ultrasound before and after coronary balloon angioplasty were performed. Forty consecutive patients (7 female, 33 male, aged 58 +/- 9 years) with 49 dilated lesions were examined with a 3.5 F, 20 MHz mechanical intravascular ultrasound imaging system before and immediately after coronary balloon angioplasty. Quantitative measurements of lumen area, total arterial area, plaque area and arterial stretch were performed in the dilated vessel segments. Plaque reduction accounted for 65% and vessel wall stretch for 35% of the total increase in luminal patency after angioplasty. In 34/49 (69%) lesions plaque reduction and in 15/49 (31%) arterial stretch contributed most (> 50%) of the overall increase in luminal area post angioplasty. in lesions with an ultrasound area stenosis before PTCA larger than the mean value of the group (> or = 87%) plaque reduction contributed a significantly higher percentage to luminal gain as compared to lesions with an area stenosis < 87% (76.5 +/- 25.0 vs 52.7 +/- 29.9, p < 0.05). Conversely, PTCA resulted in a significantly greater amount of vessel walls stretch in lesions with an area stenosis < 87% (47.3 +/- 29.9 vs. 24.4 +/- 24.2; p < 0.05). In lesions with localized dissections (32/49 (65%)) after PTCA as compared to lesions without dissection a significantly greater relative reduction of stenosis (24% +/- 13% vs. 19% +/- 7%, p < 0.05) was found. Plaque reduction and to a lesser extent vessel wall stretch constitute the principal mechanisms responsible for increased luminal patency after balloon angioplasty. The amount of plaque reduction and vessel wall stretch on the overall luminal gain after PTCA is dependent on the size of area stenosis. The presence of localized dissections after angioplasty correlates favorably with a better result.

[Occupational rehabilitation after percutaneous transluminal coronary angioplasty (PTCA)--correlation with subjective and objective parameters]

On the basis of medical criteria percutaneous transluminal coronary angioplasty (PTCA) is followed by only a short interval of work inability. This study evaluated the interval between PTCA and the return to work and the factors which may influence this interval. The study included 122 working patients with angiographically successful PTCA. Patients were followed up clinically and angiographically and completed a standardized questionnaire directly after PTCA and 4 months later. The study population comprised 87 patients (81 men, 6 women) who filled out both questionnaires appropriate for evaluation. Of these 48 (55%) had single-vessel, 27 (31%) two-vessel, and 12 (14%) three-vessel disease. Complete revascularization in terms of treatment of all lesions above 70% was achieved in 85 (98%) patients. In 30 (34%) patients restenosis developed during the observation period as evaluated by coronary angiography. At the time of the second evaluation 46 (53%) patients complained of persisting or new thoracic pain, which they understood as cardiac pain. After 4 months 68 (78%) patients returned to work, 12 (14%) were on sick leave, 3 (3%) were unemployed, and 4 (5%) were retired. The median of time on sick leave after PTCA was 14 days. The length of sick leave after PTCA was found to depend significantly on the previous intention to retire (25% vs. 75%, p < 0.01). Patients who did not return to work during study period reported more frequently of thoracic pain (55% vs. 45%, p = 0.01) and had less intention to return to work after PTCA (6% vs. 94%, p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

[Dissection following balloon angioplasty: predictive possibilities using pre-interventional intravascular ultrasonography]

The purpose of this study was to examine the association between qualitative and quantitative lesion characteristics before and the incidence of dissection after balloon angioplasty as assessed by intravascular ultrasound imaging. Thirty-seven patients (5 women, 32 men, aged 60 +/- 9 years) with 41 dilated lesions were examined with a 3.5 F, 20 MHz rotational tip intravascular ultrasound imaging system before and immediately after coronary balloon angioplasty. Images were assessed for plaque composition, topography and postinterventional effects on the plaque morphology. Quantitative measurements of lumen area, total arterial area and plaque area were performed in the dilated vessel segment. Plaque morphology was concentric in 18 lesions (44%) and eccentric in 23 lesions (56%). Fourteen lesions (34%) showed no calcification, 15 lesions (37%) were superficially and 12 lesions (29%) were deeply calcified. Four distinct changes of the plaque morphology were manifested by ultrasound imaging after balloon angioplasty. Dissection with detachment of the plaque from the underlaying wall was found in 10 lesions, plaque splitting in 9 lesions, superficial tears in 6 lesions, and smooth plaque contours in 16 lesions. The incidence of dissection detected by intravascular ultrasound was significantly greater in eccentric lesions (p = 0.03) and in stenoses with a small total arterial area (p = 0.006). The incidence of dissection was significantly increased in vessels in which balloon cross-sectional area exceeded 50% of the total cross-sectional vessel area as compared to those with a smaller balloon-to-vessel ratio. Preinterventional IVUS imaging provides information about the target stenosis which can be used to assess the risk of postinterventional dissections. In addition to the size of the balloon in relation to vessel cross-sectional area, the features small total vessel cross-sectional area and eccentric stenosis morphology in the preinterventional IVUS study predispose to an increased risk of dissection. Further studies have to elucidate the influence of dissections on late outcome after angioplasty.

The effect of LDL apheresis on progression of coronary artery disease in patients with familial hypercholesterolemia. Results of a multicenter LDL apheresis study

This study investigated the effect of extracorporal lipid-lowering therapy by low-density lipoprotein (LDL) apheresis on coronary artery disease in a population characterized by early development and rapid progression of atherosclerosis. We treated 32 patients aged between 15 and 63 years with drug-refractory familial hypercholesterolemia, treated once a week by immuno-specific LDL apheresis for 3 years in a controlled prospective and non-randomized trial; 25 patients (14 females and 11 males) completed the study. Noninvasive data were obtained by physical examination, 12-lead ECG and exercise testing. Invasive cardiological data were obtained by cardiac catheterization according to a standardized protocol in four cardiological centers. Left ventricular ejection fraction was calculated using planimetry. Coronary stenoses were measured quantitatively in 23 defined coronary segments by a panel of four investigators with an electronic digital caliper. In addition, overall coronary atherosclerosis was visually qualified. Final decisions on a classification into one of three groups (regression, no change, progression) of coronary atherosclerosis were based on panel consensus. Six cardiac events occurred throughout the study: percutaneous transluminal coronary angioplasty in one patient, coronary bypass grafting in three and two deaths. Statistical analysis of exercise testing yielded no significant change for maximum power and work capacity during the study period. Hemodynamic data revealed no significant change; mean ejection fraction was calculated as 65.8 +/- 15.9% at study entry and 67.0 +/- 12.7% at completion. Quantitative measurement of 111 circumscribed coronary stenoses showed a mean stenosis degree of 45 +/- 26% at entry cineangio-film and 43 +/- 22% at final cineangio-film demonstrating no significant change.(ABSTRACT TRUNCATED AT 250 WORDS)

[Psychosocial problems of adolescents and adults with congenital heart defects]

Despite successful medical treatment and hemodynamic good results after surgical correction, relevant psychosocial problems occur in adult patients with congenital heart disease. 146 patients in Germany with simple but also with complex congenital heart defects were examined by means of a questionnaire to look into these problems. Although most of the patients belonged to Ability Index I or Ability Index II of J. Somerville, almost 60% felt not healthy and impaired. The level of education was above average. 98% had attended a regular school, 23% a secondary school, and 15% had attended university. The congenital heart disease negatively affected the choice of occupation for 25% of the patients, but only 8.6% had difficulties when they applied for a job. The majority of patients was employed and satisfied with their occupation. Most of them were working in physically less demanding jobs. Sporting activities were widespread, although half of the patients felt impaired by the congenital heart disease when performing sports. All patients had some kind of health insurance. Most of them were enrolled in the common public health insurance plan. The insurers paid for almost all expenses caused by the congenital heart disease. More than 30% were not accepted by life insurance companies. Only 1.4% were members of a self-help-group for congenital heart disease. The knowledge of these occurring problems may help to improve the treatment of adult patients with congenital heart disease and, moreover, infants and adolescent patients who still have to reach adulthood may later benefit from this information.

[Follow-up and characteristics of restenoses after coronary stent implantation in asymptomatic patients and patients with few symptoms]

Following coronary Palmaz-Schatz single stent implantation 50 patients had an angiographic follow-up after 4-6 and after 12 months. Quantitative angiography revealed that the restenosis process has finished 4-6 months after stent implantation in the majority of patients. In the present study, 6% had, however, developed symptomatic restenosis at 1-year follow-up. Detailed assessment of 15 patients revealed that the residual stenosis after stent implantation is most prominent at the stent edges, however, restenosis did occur in all segments in about the same amount. Analysis of several clinical and morphologic variables did not reveal any particular risk factor for the development of restenosis. The results of the present study do suggest that follow-up angiography should be performed 4-6 months after stent placement.

[Local vascular complications in heart catheter studies]

Over a period of 30 months (1. 1. 89-30. 6. 91) 3516 patients who had either a diagnostic (2718) or therapeutic (798) heart catheterization were followed for local vascular complications. 774 patients were investigated prospectively. The following complications were observed in declining frequency: 1. relevant haematoma, 2. pseudoaneurysm, 3. arteriovenous fistula, 4. arterial thrombosis/dissection, 5. venous thrombosis, 6. rupture of the vessel, 7. local infection. The total complication rate was 2.22%. With prospective investigation it was significantly higher (3.23%) than with retrospective investigation (1.93%). The complication rate was also significantly higher in therapeutical procedures (3.76%) than in diagnostic catheterizations (1.76%). Factors associated with a significantly higher incidence of local vascular complications were age (p < 0.01), female gender (p < 0.025), manifest arterial hypertension (p < 0.005), aortic regurgitation (p < 0.1), peri-interventional medication with acetylsalicylic acid and full dose heparin (p < 0.001), full dose heparin alone (p < 0.001) or fibrinolysis-therapy (p < 0.025). Relevant technical factors were: duration of the procedure, duration of the placement of the catheter-sheath, French size of the catheter, left femoral access, arterial and venous access at one extremity. In about half of the cases the treatment of the complications was conservative, in the other half it was surgical (51%). In relation to all surgically treated patients the percentage of emergency operations was 25%, the percentage of reoperations was 15%.

A unique scenario for coronary atherectomy

Despite several attempts, balloon angioplasty of a slightly eccentric stenotic lesion in the proximal right coronary artery failed to result in any increase of luminal diameter. Following disruption and partial removal of a fibrous atherosclerotic cap using directional atherectomy, subsequent balloon angioplasty was highly successful.

[Clinical experiences with four newly developed, surface modified stimulation electrodes]

Newly developed pacing electrodes with so-called porous surfaces promise a significantly improved post-operative pacing and sensing threshold. We therefore investigated four newly developed leads (ELA-PMCF-860 n = 10; Biotronik-60/4-DNP n = 10, CPI-4010 n = 10, Intermedics-421-03-Biopore n = 6) connected to two different pacing devices (Intermedics NOVA II, Medtronic PASYS) in 36 patients (18 men, 18 women, age: 69.7 +/- 9.8 years) suffering from symptomatic bradycardia. The individual electrode maturation process was investigated by means of repeated measurements of pacing threshold, electrode impedance in acute, subacute, and chronic phase, as well as energy consumption and sensing behavior in the chronic phase. However, with the exception of the 4010, the investigated leads showed largely varying values of the pacing threshold with individual peaks occurring from the second up to the 13th week. All leads had nearly similar chronic pacing thresholds (PMCF 0.13 +/- 0.07; DNP 0.25 +/- 0.18; Biopore 0.15 +/- 0.05; 4010 0.14 +/- 0.05 ms). Impedance measurements revealed higher, but not significantly different values for the DNP (PMCF 582 +/- 112, DNP 755 +/- 88, Biopore 650 +/- 15, 4010 718 +/- 104 Ohm). Despite differing values for pacing threshold and impedance, the energy consumption in the chronic phase during threshold-adapted, but secure stimulation (3 * impulse-width at pacing threshold) were comparable.

A prospective, randomized, and double-blind trial on the effect of fish oil on the incidence of restenosis following PTCA

Restenosis after successful coronary angioplasty (PTCA) occurs in 25-35% of all procedures. To date, most pharmacologic strategies have failed to reduce the restenosis rate significantly. However, recent studies have suggested a potential benefit of dietary supplementation with omega-3 fatty acids (fish oil) on restenosis following PTCA. The benefit of omega-3 polyunsaturated fatty acids on the incidence of coronary artery restenosis following elective PTCA was assessed in 212 consecutive patients (41 female, 171 male). Following a successful angioplasty, 204 patients received a dietary supplementation with either nine capsules containing fish oil (3.15 g omega-3 fatty acids) or nine placebo capsules containing olive oil. Treatment was started immediately after PTCA and maintained over 4 mon. Compliance was assessed by analysis of lipid fatty acids prior to angioplasty and at 4 mon follow-up. The angiographically determined incidence of restenosis (stenosis diameter > 50%) was 31.2% per lesion in patients receiving fish oil and 33.7% in patients receiving olive oil. Gross progression of coronary artery disease in vessels not subjected to angioplasty was 17% and 16%, respectively. In conclusion, low dose fish oil supplementation begun on the day of a successful coronary angioplasty failed to demonstrate any effect on coronary artery restenosis.

[Long-term effects of low dosage fish oil on serum lipids and lipoproteins]

In a prospective and double-blind study, the long-term effects of low dose fish oil on serum lipids and lipoproteins was tested in patients with normal or moderately elevated serum lipids and compared to the effects of olive oil. The compliance to the study medication was evaluated by analysis of serum fatty acids and proved to be very good. Dietary supplementation with 9 g fish oil, respective 3.15 g n-3 fatty acids per day over one year resulted in a decrease of serum-triglycerides by 26% and increase of HDL-cholesterol by 26%. Treatment with 9 g olive oil resulted in an 18% increase of HDL-cholesterol. There was no effect on serum-triglyceride levels.

Functional health status in male patients without restenosis following successful PTCA

In a prospective pilot study, subjective and objective parameters of the health status were assessed in 148 male patients (mean age 56 +/- 8.4 years) before and 4 months after successful coronary angioplasty (PTCA). Restenosis was defined as residual diameter stenosis > 50%. Although 96 patients (65%) had not developed restenosis at 4 months' invasive follow-up, subjective assessment of general well-being was unchanged in 26% or worse in 71%; overall anginal status and exercise performance had however improved. Of 71 men younger than 60 years who had no restenosis at follow-up, 4 men retired and 13 remained on medical leave. The striking disparity between subjective and objective parameters was not related to significant differences of age, exercise capacity, and left ventricular ejection fraction, as well as to baseline characteristics (previous myocardial infarction, extent of coronary heart disease, comorbidity) compared with 52 patients with restenosis. Thus, despite documented sustained success after PTCA, the majority of patients failed to resume the status of subjective well-being.

Cardiac involvement during and after malaria

In 22 patients without a previous history of cardiac disease, we prospectively evaluated cardiac involvement during acute malaria and 9 +/- 5 months after recovery using non-invasive methods including resting electrocardiogram (ECG) and two-dimensional (2D) echocardiography. During the acute phase ECG abnormalities were common (5/22); pericardial effusion was found in 2 patients and global left ventricular hypokinesia in 1 patient infected with Plasmodium falciparum. At a follow-up of 19 patients, the resting ECG and echocardiography were normal or had normalized in all patients. The results of our study suggest that persistent cardiac damage following malarial infection seems to be rare; however, further trials in a larger patient population are needed to confirm our findings.

A prospective study on percutaneous coronary angioscopy with different guiding techniques in patients with coronary heart disease

The technical success of percutaneous coronary angioscopy using different guiding techniques was evaluated in 17 patients before (n = 17) and after (n = 8) coronary angioplasty. Steering the angioscope along or over a guidewire was successful in both groups; failures were predominantly due to insufficient alignment of the angioscope using along-the-wire guiding. Although over-the-wire angioscopy promises superior guiding and alignment capabilities, several technical problems remain unsolved.

New option for balloon recanalization of total coronary occlusions

In 9 out of 12 patients with a total coronary occlusion but definite signs of viable myocardium a new approach for the recanalization procedure was successfully employed: Following recanalization using an on-the-wire 2.0 or 2.5 mm angioplasty catheter, a standard coronary guidewire was placed along the angioplasty catheter. After withdrawal of the catheter, over-the-wire angioplasty with an appropriately sized balloon was performed for final dilatation. Pending further studies in a larger patient population, this new method may offer an alternative approach for revascularization of total coronary occlusions.

Failure of radiotherapy to resolve fatal lung damage due to paraquat poisoning

The most effective treatment of severe paraquat poisoning in man is uncertain. In order to prevent pulmonary fibrosis, we employed radiotherapy of both lungs in a 23-year-old patient with severe paraquat poisoning; however, it failed to prevent the fatal outcome.

Cardiopulmonary exercise testing (CPX) and transthoracic bioimpedance measurements: new tools for an "old disease" (congestive heart failure)

The purpose of the study was to examine the cardiovascular and cardiopulmonary exercise capacity in patients with symptomatic congestive heart failure more exactly than with conventional investigations, using the simultaneous non-invasive determination of the gas exchange parameters (ergospirometry, CPX) and of the hemodynamic (transthoracic bioimpedance). The reproducibility of the data were measured with each method with repeated tests under the same conditions in healthy subjects and patients with myocardial failure. Therefore we tested 15 patients with documented congestive heart failure repeatedly on a bicycle (semi-supine, +15 watts/min, symptom-limited). The ergospirometric (VO2, VCO2, RER = VCO2/VO2, max. VO2, VO2AT, VE, RR) and the bioimpedance-parameters (CI, SVI, HR) were measured simultaneously during rest and exercise. According to Wasserman et al. we used the VO2AT and the max. VO2 to assign the patients to the different Weber classes: Weber A: greater than 20 ml/min/kg max. VO2, greater than 14 ml/min/kg VO2AT; Weber B: 16 to 20 ml/min/kg max. VO2, 11 to 14 8 to 11 ml/min/kg VO2AT; Weber D: 6 to 10 ml/min/kg max. ml/min/kg VO2AT; Weber C: 10 to 16 ml/min/kg max. VO2, 8 to 11 ml/min/kg VO2AT; Weber D: 6 to 10 ml/min/kg max. VO2, 4 to 8 ml/min/kg VO2AT: Weber E: less than 6 ml/min/kg max. VO2, less than 4 ml/min/kg VO2AT. The V-slope-method according to Beaver et al. allowed for the determination of the anaerobic threshold in 13/15 patients. 2/15 patients didn't reach the anaerobic threshold. Oscillations of the gas exchange parameters due to Cheyne-Stokes-breathing were found in 9/15 patients.(ABSTRACT TRUNCATED AT 250 WORDS)

Left hemitruncus in adulthood: diagnostic role of magnetic resonance imaging

The diagnosis of left hemitruncus and large patent ductus arteriosus was made by magnetic resonance imaging in an adult patient with recurrent haemoptysis and dyspnoea on exertion. Previous cardiac catheterization and echocardiography failed to establish the complete diagnosis. Magnetic resonance imaging using spin-echo and gradient-echo pulse sequences is a useful imaging modality to evaluate anatomical and functional abnormalities in patients with complex congenital heart disease.