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Biomedical subjects

T Bonzel

Publications and source records attributed to T Bonzel.

At least 37 records · Page 2Linked to original sources
PubMed1994

[Quality assurance in PTCA].

The special need for quality assurance in PTCA results from increasing numbers of procedures, which are due to the prevalence of disease, high primary success rates, progressive simplicity of the basic procedure, but guaranteed financing in Germany. Quality assurance programs first have to take into account the procedural quality, which includes preparation, performance, result, and also overall appropriateness (the indication) of PTCA, and secondly, the structural quality, including personnel, organization, cardiac laboratory facilities and technical equipment. In spite of numerous publications addressing special issues relating to PTCA, these items have been largely neglected in research, and it is uncertain which parameters and methods are meaningful for the improvement of clinical quality and effectiveness. Two examples for general and for internal quality control are demonstrated. In a first extensive quality assurance project of the ALKK study group, all PTCA procedures of a complete group of hospitals are prospectively registered on an intention-to-treat basis, data are controlled by visiting monitors, and appropriateness is examined in a representative sample of procedures by evaluating complete patient files. As an example for an internal quality control system a software program (CLAIM, cardiac laboratory angiography investigation management) is presented. The program yields clinical data but also investigator-related parameters such as fluoroscopy time, investigation time, contrast use, balloon consumption, etc.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

[Life-threatening arterial bleeding in hemorrhagic-necrotizing salmonella ileitis].

A 23-year-old man in otherwise good health had diarrhoea for two days during a holiday on Maldives. Two months later he suddenly collapsed and had to be admitted to hospital. Haemoglobin concentration was found to be 76 g/l, with a haematocrit of 0.22, WBC count of 17,800/microliters and platelets of 22%. Massive passage of bright red blood in the stools (none previously) could not be explained by abdominal sonography, oesophagogastroduodenoscopy, coloscopy, technetium scintigraphy or angiography of the superior mesenteric artery. Exploratory laparotomy revealed severe inflammatory changes in the terminal ileum with enlargement of the regional lymph-nodes and spurting bleeding from a branch of the ileocolic artery. Histological examination showed focal necrotizing, ulcerative and haemorrhagic ileitis. After ileocaecal resection and end-to-end anastomosis to the ascending colon the patient quickly recovered. Salmonella Livingstone was isolated from the stool and the infection was treated with ciprofloxacin, 200 mg twice daily intravenously for 5 days. Subsequent stool samples were negative but follow-up continues.

Adult↗
PubMed1993

[Coronary stent implantation: infection and abscess with fatal outcome].

We report a case of coronary stent-implantation using a Palmaz-Schatz-stent in the right coronary artery (RCA) of a 66-year old woman. Coronary stenting was performed following local dissection and high-grade stenosis after PTCA. Following stent thrombosis re-PTCA was successful, but within 4 weeks progressive reduction of the patient's general condition, plus leucocytosis, subfebril temperatures, and a pericardial effusion occurred. Transesophageal echocardiography documented a perivascular myocardial abscess near the RCA stent; puncture demonstrated pericardial empyema. Emergency cardiac operation was done with segmental resection of the destructed RCA, stent explantation, and CABG to the peripheral RCA, but the patient died. To our knowledge, this is the first case of stent infection reported in the international literature. Transesophageal echocardiography was very helpful in diagnosing this fatal complication of coronary stenting.

Abscess↗
PubMed1992

[Acute and intermediate clinical and angiography results after coronary stent implantation].

The value of stenting in emergency situations in interventional angioplasty procedures is widely accepted. Stenting remains controversial as a therapeutic method for use beyond the acute phase, as the results reported in the acute phase are characterized by a wide range. This study reports the implantation results of Palmaz-Schatz stents in 64 cases mostly for failed PTCA. Stents were mounted on Monorail-PVC-balloon catheters. The acute success rate was 96.8%. In two cases with stent misplacement CABG was performed within 48 h. No lethal events occurred in the acute phase. Stent thrombosis has only been seen in four cases (6.5%) so far under subtle monitoring of the anticoagulant regime. Restenosis rate (definition: NHLBI-4) according to serial angiography 6 and 12 weeks after implantation was 4.25% at 6 weeks, with a cumulative rate of 19.4% up to 12 weeks. All recurrences eligible for PTCA have been successfully redilated. A high extracardiac complication rate--predominantly groin hematoma--is the main disadvantage of the procedure. Surgical repair was necessary in 11.4% up to 6 weeks after implantation. Surprisingly high was also the incidence of hematuria, also in 11.4%, in the phase of high anticoagulation. In conclusion, stenting is an effective therapeutic method to avoid emergency CABG and elective CABG in most cases of failed PTCA.

Adult↗
PubMed1992

[The potential significance of early effort myocardial scintigraphy following PTCA].

Exercise 201Tl scintigraphy before and after successful PTCA was evaluated in 69 patients with coronary stenosis > 60%. Mean luminal stenosis was found reduced from 74 +/- 10% to 31 +/- 11% (58% reduction). Scintitomographic examination within 3 weeks following intervention showed a reduction of the exercise perfusion defect from 17.00 +/- 14.6 to 5.8 +/- 7.8 arbitrary units (66% reduction). Angiographically, re-stenosis was identified in 22/41 patients (54%) after 6 months. Unexpectedly, re-stenosis could not be predicted by early 201Tl scintigraphy (positive and negative predictive value in patients with single-vessel disease: 61% and 41%, resp.). Nevertheless, evaluation of PTCA results was possible (sensitivity 83%). However, postinterventional transient defects, indicating ischemia, were often seen (all patients: 43/69; patients with single-vessel disease: 31/55) and not indicative of failure of the intervention. Thus, post-PTCA scintigrams should be compared with scintigrams recorded before the intervention to ensure reliable follow-up control.

Adult↗
PubMed1989

Myocardial energetics in patients with dilated cardiomyopathy. Influence of nitroprusside and enoximone.

Cardiotonic agents influence myocardial energy consumption by vasodilation, which may reduce energy demand, and by inotropism, which may increase it. To distinguish between the two effects, myocardial oxygen consumption must be analyzed in relation to its hemodynamic determinants. The coupling of myocardial oxygen consumption with its determinants was investigated in 22 patients with idiopathic dilated cardiomyopathy (NYHA Class II and III). Predicted myocardial oxygen consumption by the pressure-work index, the Bretschneider index, and the pressure-volume area correlated moderately with measured myocardial oxygen consumption (r = 0.57, p less than 0.001; r = 0.52, p less than 0.005; and r = 0.63, p less than 0.001). Multiple regression analysis, including left ventricular peak systolic wall stress, systolic stress-time integral, pressure-volume work, maximum rate of left ventricular pressure rise, and mean velocity of circumferential fiber shortening indicated that systolic stress-time integral is the major determinant of myocardial oxygen consumption (r = 0.75, p less than 0.001) in these patients. Enoximone, a phosphodiesterase inhibitor, has an inotropic and a vasodilating effect. To investigate the inotropic portion of the energy cost of this phosphodiesterase inhibitor, the influence of enoximone on myocardial oxygen consumption and systolic stress-time integral was compared with the effects of nitroprusside, which is a vasodilator only. Nitroprusside (10 patients) and enoximone (12 patients) reduced left ventricular systolic stress-time integral from 109 +/- 22 to 71 +/- 21 (p less than 0.005) and from 104 +/- 23 to 42 +/- 10 (p less than 0.001) 10(3) dynes.sec/cm2, respectively. Myocardial oxygen consumption decreased from 159 +/- 44 to 112 +/- 23 (p less than 0.005) and from 134 +/- 28 to 109 +/- 21 (p less than 0.001) microliters/beat/100 g, respectively. In both groups, there was a significant correlation between the decrease in myocardial oxygen consumption and the decrease in systolic stress-time integral. The slopes of the respective linear regression lines were significantly different (1.27 for nitroprusside and 0.51 nl.cm2/100 g.dynes.sec for enoximone, p less than 0.05), indicating a smaller decrease of myocardial oxygen consumption for a given decrease of stress-time integral with enoximone. Applying the pressure-work index or the pressure-volume area instead of systolic stress-time integral yielded comparable results. Thus, vasodilation reduces myocardial oxygen consumption in proportion to the reduction of stress-time integral. With enoximone, the energy-saving effect of vasodilation is counteracted in part by the increased energy d

Adult↗
PubMed1989

Flow-dependent coronary artery dilatation in humans.

To determine the role of endothelium-mediated flow-dependent coronary dilatation in humans, we studied the coronary dilatation exerted by maximal pharmacologic increase of coronary flow in 14 patients with normal coronary arteries. Biplane views of the circumflex (Cx) and left anterior descending (LAD) coronary arteries were obtained before and 80 seconds after inducing a maximal increase in flow selectively in the Cx by injecting 7 mg papaverine through a 2F infusion catheter in the midportion of the Cx (n = 10). The diameter of the proximal Cx segment (exposed to increased flow but not to papaverine directly) increased with papaverine by 11.1 +/- 4% (range, 5.2-16.4%, p less than 0.001 vs. control), whereas the LAD diameter did not change. LAD and Cx diameters increased by 18.3% and 21.2% after nitroglycerin given into the left main artery, which showed the preserved capability of the LAD to dilate. In four patients with normal coronary arteries and six patients with coronary artery disease (CAD, non-flow-limiting stenosis), a similar protocol was applied with the LAD for the assessment of flow-dependent dilatation. Simultaneously, intracoronary blood flow velocity was measured by an intracoronary Doppler catheter. Papaverine-induced coronary flow reserve (peak/resting velocity ratio) in the LAD was 4 +/- 0.7 (range, 3.5-5) in normal arteries and was 3.5 +/- 0.6 (range, 2.7-4.4) in CAD.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1987

Hemodynamics and myocardial oxygen metabolism of pulsus alternans in patients with dilative cardiomyopathy.

The hemodynamic and myocardial energetic changes due to pulsus alternans were investigated by left and right heart catheterization and by oxygen consumption measurements in three patients with dilative cardiomyopathy. In all three patients, pulsus alternans developed after intravenous administration of the phosphodiesterase inhibitor enoximone. Following enoximone (Patients 1/2/3), left ventricular peak systolic pressure was reduced, in the respective patients, from 100/103/115 mmHg (normal beat) to 91/96/94 mmHg (strong beat) and further to 59/80/85 mmHg (weak beat); left ventricular end-diastolic pressure was reduced from 24/23/22 mmHg (normal beat) to 5/10/6 mmHg (strong beat) and further to 3/7/4 mmHg (weak beat). Cardiac output increased by an average of 16%. Heart rate increased by an average of 12%. Stroke work (during pulsus alternans mean between strong and weak beats) did not change (less than 5%) in any of the three patients. Arterial-coronary-sinus oxygen content difference decreased by 5%/13%/22, respectively. Myocardial oxygen consumption per beat decreased in Patient 1 by 8%, in Patient 2 by 8% and remained unchanged in Patient 3. It is concluded that pulsus alternans occurred in consequence of alternating systolic performance. The alternation in systolic performance most probably resulted from a disturbance in excitation-contraction coupling induced by enoximone. The pronounced reduction of left ventricular preload following administration of enoximone may have augmented further the differences between the strong and the weak beat. A disturbance in myocardial oxygen metabolism was ruled out as the cause of pulsus alternans in these patients.

Adult↗
PubMed1987

Influence of phosphodiesterase inhibition on myocardial energetics in dilative cardiomyopathy.

The effects of inhibition of phosphodiesterase by enoximone on left ventricular haemodynamics and myocardial energetics were investigated in 10 patients with idiopathic dilative cardiomyopathy. After intravenous administration of enoximone, there was a significant reduction of left ventricular systolic pressure from 126 +/- 21 to 93 +/- 16 mm Hg, of left ventricular end-diastolic pressure from 16 +/- 8 to 5 +/- 3 mm Hg and of left ventricular end-diastolic volume from 287 +/- 54 to 215 +/- 69 ml. Left ventricular pressure-volume work decreased significantly from 12.1 +/- 3.6 to 7.6 +/- 2.8 mm Hg.l. Heart rate was 87 +/- 17 before and 103 +/- 18 min-1 after administration of enoximone (p less than 0.01). Left ventricular systolic stress-time integral, a major determinant of myocardial oxygen consumption, decreased by 49% from 91 +/- 32 to 46 +/- 15 10(3) dyn.s/cm2 (p less than 0.01). In contrast myocardial oxygen consumption per beat was reduced by only 18%, from 138 +/- 28 to 113 +/- 17 microliters O2/100 g (p less than 0.01). The economy of myocardial contraction as calculated by the ratio of systolic stress-time integral to myocardial oxygen consumption per beat was 675 +/- 192 before and 370 +/- 128 dyn.s.100 g/cm2.microliter O2 after administration of enoximone. In conclusion, the phosphodiesterase inhibitor enoximone exhibits vascular and myocardial effects. The myocardial effects result in decreased economy of myocardial contraction. The possible molecular mechanisms of these energetic changes are discussed.

Cardiomyopathies↗
PubMed1987

Acute surgical intervention for complications of percutaneous transluminal angioplasty.

Since 1979, percutaneous transluminal angioplasty (PTA) resulting in an overall improvement of 80.3% has been performed in 4380 patients with occlusive atheroma of the lower extremities. Complications requiring immediate surgical treatment occurred in 123 (2.8%) of the cases, consisting of occlusion (16%), dissection (13%), perforation (10%), embolisation (15%) and haematoma at the puncture track (69%). Of the group treated surgically, 18 (14.6%) patients underwent amputation of a lower limb. Since 1980 348 percutaneous transluminal coronary angioplasties (PTCAs) have been performed for coronary artery disease. In 15 cases (4.3%) emergency coronary bypass surgery was necessary because of complications encountered with PTCA. Two patients died and perioperative myocardial infarction occurred in 7 (subendocardial-3: transmural-4). In spite of a low complication rate and good results from PTA and PCTA acute surgical intervention for complications carries a significant operative morbidity and mortality. We conclude that selection for PTA and PTCA has to involve vascular and cardiac surgeons, their presence being mandatory at institutions in which therapeutic radiological procedures are undertaken.

Angioplasty, Balloon↗
PubMed1987

Hierarchy of levels of ischemia-induced impairment in regional left ventricular systolic function in man.

We tested the hypothesis that different subsets of ischemia-induced wall motion disorders are characterized by specific patterns of abnormal regional left ventricular systolic function. Regional contraction was quantitatively assessed from two-dimensional echocardiograms by an automated integrative analysis considering the time course of wall motion during the entire contraction sequence in 20 patients with chronic myocardial infarction, in 13 patients with impending myocardial infarction (less than 2 hr after the onset of symptoms), and in nine patients during transient myocardial ischemia. Wall motion abnormalities were detected in all patients by the integrative analysis. In contrast, the sensitivity for detecting wall motion abnormalities was 80% during chronic infarction, 77% during impending infarction, and 56% during transient ischemia if only end-diastolic and end-systolic frames were compared for assessment of overall regional systolic function. There were distinct differences in the time course of abnormal wall excursion between the three groups. Chronic infarction was characterized by a monophasic contraction pattern, with abnormal synergy in regional contractile events occurring predominantly during early systole. In contrast, transient ischemia caused predominantly mid-to-late systolic abnormal synergy followed by late systolic shortening corresponding to a polyphasic contraction pattern. During impending infarction, an intermediate temporal contraction pattern was present with both early and mesosystolic abnormal synergy.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1987

Early clinical evaluation of the intravenous treatment of acute myocardial infarction with anisoylated plasminogen streptokinase activator complex.

50 consecutive patients with acute myocardial infarction and symptoms of less than 4 hours duration were treated with anisoylated plasminogen streptokinase activator complex (APSAC) 30U intravenously as a bolus injection over 5 minutes. An open infarct-related artery was found in 32 patients (64%) when the first coronary angiography was taken 66 +/- 21 minutes after APSAC. Complete reperfusion was subsequently seen in 10 of 18 patients with an occluded infarct-related artery 74 +/- 16 minutes after injection of APSAC. Thus, a patient infarct-related artery was seen in 42 patients (84%) within 68 +/- 20 minutes. A control coronary angiography was performed in 37 patients (74%) after 25 +/- 19 days. Reocclusion was found in 5 patients. The minimal cross-sectional area of the residual coronary stenosis increased from 1.3 +/- 0.9 mm2 to 1.8 +/- 1.9 mm2. Patients with residual thrombi after coronary thrombolysis (n = 13) demonstrated an increase of the minimal cross-sectional area of the residual stenosis from 1.2 +/- 0.8 to 2.6 +/- 2.3 mm2, whereas those without residual thrombi showed only minor changes of the minimal cross-sectional area (1.3 +/- 0.9 to 1.2 +/- 1.2 mm2). Thus, APSAC demonstrated a high patency rate and a low reocclusion rate after intravenous administration. The prolonged fibrinolytic activity of APSAC leads to a further regression of the residual coronary stenosis among patients with coronary thrombi after reperfusion.

Adult↗
PubMed1987

The sliding rail system (monorail): description of a new technique for intravascular instrumentation and its application to coronary angioplasty.

The sliding rail technique is a new technique for intravascular instrumentation, especially coronary stenosis dilatation. The so-called monorail balloon catheter is the first device which can be used according to this technique. The monorail catheter has a single lumen shaft and only a short central tube within the distal balloon part. With the guidewire inserted into the tube, the balloon can be advanced or retracted on the guidewire as on a sliding rail. The most relevant improvements for coronary dilatation are steerability, contrast flow and rapid and easy exchangeability of balloon catheters and other intracoronary devices. These characteristics are felt to result in a more simple and time- and fluoroscopy-saving dilatation procedure. A special transfusion catheter may also improve procedural safety. The first clinical results in 69 patients with a success rate of 96%, an emergency bypass rate of two patients (one infarction) and a stenosis improvement of 58% confirm the theoretically conceived advantages.

Adult↗