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Biomedical subjects

K H Scholz

Publications and source records attributed to K H Scholz.

At least 19 recordsLinked to original sources
PubMed2001

Massive pulmonary embolism with large floating thrombus in the truncus of the pulmonary artery.

A conservative strategy with anticoagulation led to spontaneous dissolution of a large floating thrombus (7.0x0.5 cm) in the truncus of the pulmonary artery in a 51-year-old woman with massive pulmonary embolism (pulmonary emboli in both lungs down to the level of the segmental arteries). Interventional therapy such as thrombolysis or pulmonary thrombectomy was not considered to be appropriate for this patient because of the risk of disrupture and embolization of parts of this large central thrombus. We believe that in certain cases with massive pulmonary embolism and large floating central thrombi a conservative strategy with anticoagulation may be appropriate. Such cases may be observed more often in the future using the technique of spiral computed tomographic angiography.

Anticoagulants↗
PubMed1999

Determinants of stent restenosis in chronic coronary occlusions assessed by intracoronary ultrasound.

Chronic coronary occlusions have a high recurrence rate that can be reduced by stenting, but this rate remains higher than in nonocclusive lesions. To analyze possible determinants of restenosis in these lesions, intracoronary ultrasound was performed during the recanalization procedure. A chronic coronary occlusion of > or = 1 month duration (range 1 to 33 months; median 3.3) was successfully recanalized in 41 patients. Quantitative ultrasound analysis was performed before and after stent placement, with measurement of the luminal area, the extent of the plaque burden at the site proximal and distal to the occlusion, and within the occlusion and the subsequent stent. The degree of compensatory enlargement of the coronary artery within the occlusion was determined by comparing the average of the total vessel area of the proximal and distal reference with the lesion site. Early reocclusion (subacute stent thrombosis) was observed in 1 patient (2.4%). The angiographic control after 6 months showed restenosis in 9 patients with 1 late reocclusion. The overall recurrence rate was 24%. There was no difference in clinical and procedural characteristics between lesions with restenosis and without restenosis. The latter had a larger minimum stent area (7.59 +/- 1.96 mm2 vs 5.71 +/- 0.90 mm2; p <0.01), and there was evidence for more compensatory vessel enlargement in lesions without restenosis. Thus, intracoronary ultrasound showed that a smaller minimum stent area was a major predictor of angiographic restenosis, and it occurred more often in occlusions without compensatory vessel enlargement.

Angioplasty, Balloon, Coronary↗
PubMed1999

[Experiences with temporary vena cava filters in 114 at-risk patients with thrombosis or thromboembolism].

BACKGROUND AND OBJECTIVES: The indications for temporary implantation of a vena cava filter remain unclear and there are as yet few data about its complications and reliability. It was the aim of this study to determine the efficacy and complication rate of the temporary use of a vena cava filter (VCF) in a large group of patients at high risk of pulmonary embolism, and thus contribute to defining the indications for such temporary implantation. PATIENTS AND METHODS: Between November 1991 and October 1997 a total of 118 VCF were implanted in four groups of a total of 114 patients (67 women, 47 men; average age 45.3 +/- 19.8 [12-82] years) to prevent pulmonary embolism: those (1) with massive or fulminant pulmonary embolism (n = 54); (2) with mechanical thrombus fragmentation and (or) local catheter-delivered systemic thrombolysis in pelvic, leg or caval vein thrombosis (n = 42); (3) with systemic thrombolysis in case of floating thrombi at the femoral, iliac or caval veins (n = 7); and (4) as perioperative measure in caesarean section, venous thrombectomy, other surgical interventions or when anticoagulation had to be discontinued in patients with deep vein thrombosis (n = 11). RESULTS: Filters remained implanted for a mean of 6.1 +/- 3.4 (1-16) days. Placement had to be corrected because of filter dislocation in eight patients. Proven pulmonary embolism occurred after filter implantation in only one patient, after filter displacement into the unthrombosed contralateral iliac vein. Thrombus deposition on the filter before its removal was demonstrated in nine patients: thrombolysis was effective in seven of them, while thrombosed filters had to be removed surgically in two. Residual thrombi were found on the filter in six further patients. No pulmonary embolism occurred in connection with filter removal. Local complications at or around the site of insertion of the introducing catheter occurred in 53 of the 114 patients (46.5%): haematoma in 42, infection in 21 and brachial vein thrombosis in three patients. CONCLUSIONS: The rate of clinically relevant pulmonary embolism can probably be reduced to a minimum by the implantation of a temporary vena cava filter. The overall complication rate is high, but serious complications are rare.

Adolescent↗
PubMed1999

[Reperfusion therapy and mechanical circulatory support in patients in cardiogenic shock].

Cardiogenic shock is a state of inadequate tissue perfusion due to cardiac dysfunction, which is most commonly caused by acute myocardial infarction. The pathophysiology of cardiogenic shock is characterized by a downward spiral: ischemia causes myocardial dysfunction, which, in turn, augments the ischemic damage and the energetical imbalance. With conservative therapy, mortality rates for patients with cardiogenic shock are frustratingly high reaching more than 80%. Additional thrombolytic therapy has not been shown to significantly improve survival in such patients. Emergency cardiac catheterization and coronary angioplasty, however, seem to improve the outcome in shock-patients, which most probably is due to rapid and complete revascularization generally reached by angioplasty. In addition to interventional therapy with rapid coronary revascularization, the use of mechanical circulatory support may interrupt the vicious cycle in cardiogenic shock by stabilizing hemodynamics and the metabolic situation. Different cardiac assist devices are available for cardiologists and cardiac surgeons: 1. intraaortic balloon counterpulsation (IABP), 2. implantable turbine-pump (Hemopump), 3. percutaneous cardiopulmonary bypass support (CPS), 4. right heart, left heart, or biventricular assist devices placed by thoracotomy, and 5. intra- and extrathoracic total artificial hearts. Since percutaneous application is possible with IABP, Hemopump and CPS, these devices are currently used in interventional cardiology. The basic goals of the less invasive intraaortic balloon counterpulsation (IABP; Figure 1) are to stabilize circulatory collapse, to increase coronary perfusion and myocardial oxygen supply, and to decrease left ventricular workload and myocardial oxygen demand (Figure 2). Since the advent of percutaneous placement, IABP has been used by an increasing number of institutions (Figure 3). In addition to cardiogenic shock, the system may be of use in a variety of other indications in the catheterization laboratory and intensive care unit, including weaning from percutaneous cardiopulmonary bypass, in ischaemic left ventricular failure, in unstable angina, in high risk PTCA, and in prophylactic support in patients with myocardial infarction and successful revascularization. Animal experimental data showed that IABP may improve success of thrombolysis and recent clinical data suggest that survival is enhanced and transfer for revascularization is facilitated when patients with myocardial infarction and cardiogenic shock undergo thrombolysis and IABP rather than thrombolysis alone. A lot of studies had demonstrated before, that combined use of counterpulsation and revascularization therapy (i.e. coronary bypass surgery or angioplasty) may improve prognosis in patients with myocardial infarction complicated by cardiogenic shock (Table 1). In such patients, early treatment with IABP is most important: Multivariate analysis identified early IABP-support with a duration of shock to IABP-treatment of > or = 4 hours as an independent predictor of a positive short-term outcome. In shock-patients with postinfarction ventricular septal defect, IABP provides a marked hemodynamic improvement, and a significant decrease in shunt-flow (Figure 5). However, despite initial stabilization with IABP, such patients need immediate surgical repair of the septal defect to avoid hemodynamic deterioration. The rate of complications related to percutaneous IABP was significantly attenuated by employing catheters of reduced size. Using 9.5-F catheters, a long duration of counterpulsation emerged as the most significant factor associated with complications. In our hospital, those patients with 9.5-F catheters in whom counterpulsation did not exceed 48 hours had a low complication rate of 3.9%. The Hemopump is a catheter-mounted transvalvular left ventricular assist device intended for surgical placement via the femoral artery (Figures 6 and 7). (ABSTRACT TRUNCATED)

Cardiopulmonary Bypass↗
PubMed1998

Clinical experience with the percutaneous hemopump during high-risk coronary angioplasty.

The percutaneous Hemopump showed beneficial effects during coronary angioplasty in 32 high-risk patients with unloading of the left ventricle during ischemia and maintaining cardiac output with mean aortic pressures of 50 mm Hg in case of cardiac arrest (3 patients). High procedure-related morbidity (occlusion of femoral artery in 2 patients; bleeding with need of transfusion in 4 patients) and mortality (4 of 32 patients) rates demonstrate the need for a very careful selection of patients.

Adult↗
PubMed1998

[Intracoronary ultrasound during recanalization of chronic coronary occlusions: Relation to restenosis and reocclusion after balloon angioplasty or stent implantation].

Chronic coronary occlusions carry a high recurrence rate, and coronary stenting evolves as a preferred therapy of these complex lesions. Insight into the morphology of the occluded segment by intracoronary ultrasound may provide information which may help to improve the interventional strategy and the long-term outcome. After successful recanalization of chronic coronary occlusions (4 weeks to 33 months; median 3.2 months) in 59 patients, 29 patients were treated by balloon angioplasty alone, and 30 patients received one or more coronary stents because of complicated dissections or a high-grade residual stenosis after balloon dilatation. Intracoronary ultrasound was used to assess the lesion morphology and to quantify the angioplasty result. The luminal area, the total vessel area and the extent of the plaque burden were measured proximal and distal to the occlusion and at the narrowest site within the occlusion or the coronary stents, and the elastic recoil was calculated. Plaques in chronic occlusions were predominantly hypodense, and 44% were characterized by a multilayered plaque appearance. The elastic recoil was higher in multilayered plaques than in other plaques (46 +/- 19% vs. 34 +/- 15%; p < 0.05). Based on the quantitative ultrasound measurement after the initial balloon dilatation, it appeared that the initial balloon was undersized in 54%. The lumen area in patients with balloon angioplasty alone was increased from 4.02 +/- 1.34 mm2 to 5.49 +/- 1.47 mm2 and in the stented patients from 3.58 +/- 1.04 mm2 to 7.10 +/- 1.92 mm2. The recurrence rate in patients with balloon angioplasty was 48% with 24% reocclusions. Patients with recurrence had a slightly lower lesion area (3.97 +/- 1.41 mm2 vs. 4.71 +/- 1.44 mm2; n.s.) and minimum diameter (1.82 +/- 0.31 mm vs. 2.14 +/- 0.40 mm; p < 0.05) after dilatation. In stented patients the recurrence rate was 27% with two early stent thrombosis (6.7%) and no late reocclusion. In patients with recurrence the achieved stent area was significantly smaller than in those without restenosis (5.71 +/- 0.90 mm2 vs. 7.59 +/- 1.96 mm2; p < 0.01), and the degree of vascular remodelling at the site of the occlusion was less pronounced. Intracoronary ultrasound showed sonographic plaque characteristics in chronic occlusions which responded poorly to balloon dilatation alone. Stent implantation improved considerably the luminal area gain and could reduce the long-term outcome. To further improve the recurrence rate in stents, an optimized stent expansion should be achieved, and intracoronary ultrasound could provide an ideal tool for this purpose.

Aged↗
PubMed1998

Complications of intra-aortic balloon counterpulsation. The role of catheter size and duration of support in a multivariate analysis of risk.

AIMS: The aim of this study was to assess the risk of intra-aortic balloon counterpulsation and to identify clinical and procedural variables that would predict complications. METHODS AND RESULTS: We analysed 381 consecutive patients who were treated between 1977 and 1995 at our catheterization laboratory and/or medical intensive care unit. The complications considered relevant were limb ischaemia requiring catheter removal, vascular injury, bleeding requiring transfusion, embolic events, and infection. In eight patients the balloon could not be inserted. The rate of complications for the remaining 373 patients was 12.9%. Between 1977 and 1980, surgical insertion was performed using a 12 French catheter with a complication rate of 30.4% (seven of 23 patients). Percutaneous implantation, performed after 1981, had an overall complication rate of 11.7% (41 of 350 patients). Using thinner catheters for percutaneous placement was associated with a reduction in the rate of complications, from 20.7% (17 of 82 patients) for 12 French catheters to 9.9% (10 of 101 patients) for 10.5 French catheters (P = 0.04), and 8.4% (14 of 167 patients) for 9.5 French catheters (P = 0.006). Multivariate logistic regression analysis identified duration of counterpulsation > 48 h (odds ratio 3.6), catheter size (odds ratio 3.4 for 12 French catheters), peripheral vascular disease (odds ratio 2.7), and shock (odds ratio 2.0) as independent risk factors for counterpulsation-associated complications. When considering 9.5 French catheters only (167 patients, all after 1992), the sole remaining independent risk factor was duration of counterpulsation > 48 h (odds ratio 3.8). Those patients with 9.5 French catheters in whom counterpulsation did not exceed 48 h had a low complication rate of 3.9%. CONCLUSION: The rate of percutaneous intra-aortic balloon counterpulsation complications was thus significantly reduced by employing thinner catheters. It was at an acceptable level for 9.5 French catheters, where a long duration of counterpulsation emerged as the most significant factor associated with complications. Whether using even thinner catheters in combination with a sheathless implantation technique further minimizes the risk of counterpulsation remains to be seen.

Aged↗
PubMed1997

Vessel reconstruction in total coronary occlusions with a long subintimal wire pathway: use of multiple stents under guidance of intravascular ultrasound.

A frequent cause of failure of the recanalization of a total coronary occlusion is a subintimal pathway of the guide wire. Three cases of occluded right coronary arteries are presented in which a distal reentry into the true vessel lumen was achieved. Intravascular ultrasound was used to locate the exit and reentry of the guide wire, and to plan the position of multiple stents for the coverage of this subintimal pathway. In all cases antegrade flow to the distal coronary bed was restored.

Adult↗
PubMed1996

PTCA with the use of cardiac assist devices: risk stratification, short- and long-term results.

Percutaneous cardiopulmonary assist devices (PCPS) have become available in interventional cardiology within recent years. These tools offer the opportunity of performing percutaneous transluminal coronary angioplasty (PTCA) in high-risk patients characterized by significant stenoses of several coronary arteries and a poor left ventricular function. It is unclear for which patients PCPS are necessary and which patients will profit by PTCA as compared to coronary artery bypass grafting (CABG). Therefore, the anticipated risk of CABG and of PTCA without assist devices was calculated according to risk scores and compared with our results of assisted PTCA. In addition the long-term survival rate was investigated. In 35 patients (mean 65.5 years of age, 12 females, 23 males), we performed PTCA concomitant with the use of cardiac assist devices. The indications for the use of a cardiac assist device were severely impaired LV function (EF 30% +/- 8.9%) in combination with significant coronary artery disease (2.7 +/- 0.3 vessels) and a significant supply area of the vessel to be dilated. In 6 patients, PCPS was started before coronary angioplasty because of hemodynamic instability. In 21 cases, PCPS was on a standby basis without being connected to the patient's circulation. In 8 patients, a left heart assist device, the 14F-Hemopump, was inserted percutaneously. The patients were analyzed using risk scores of angioplasty and of coronary bypass graft surgery. The calculated risk of hemodynamic compromise during PTCA according to the risk scores was more than 50%. The anticipated risk of a fatal outcome following CABG would have been 19.8%. PTCA was performed on an average of 2.0 coronary arteries per patient and was successful in 85%. We observed a decline in angina pectoris classification (CCS) from 3.5 to 1.6. An average reduction of 1.1 NYHA class was achieved. The in-hospital mortality was 8.6% (3 patients: 1 x sepsis, 1 x early reocclusion, 1 x cerebral embolism). At 24 months follow-up, a re-PTCA was necessary in four cases because of restenosis. In the remainder, NYHA and CCS class were stable during the follow-up period. An additional five patients died during the first year and two patients in the second year. We conclude that PTCA with the use of a cardiac assist device shows favorable short-term results in a subset of patients with extended coronary artery disease and severely impaired LV function who are not suitable for nonsupported PTCA or CABG due to their risk profile. However, the long term results are not satisfying and stress the need for complete revascularisation with CABG once the patient's condition is stabilized by means of supported PTCA.

Aged↗
PubMed1996

[High risk PTCA: prevention and treatment of cardiogenic shock with mechanical assist systems].

Vessel occlusion during of after PTCA integrates the risk of pump failure if the ischemia volume is great as compared to the remaining myocardium. In so-called high-risk PTCA a risk stratification by means of risk scores such as "Bergelson Score" is mandatory. To encounter the risk of pump failure the application of mechanical cardiac assist devices such as balloon pumps, Hemopump or percutaneous applicable cardio-pulmonary support (pCPS) can be considered. To counteract ischemia during balloon inflation active perfusion balloons can be applied. The latter systems are simple and effective, however the duration of application is restricted to the balloon inflation period. Cardiac assist devices are more aggressive. While the results of intaaortic ballon pump in combination with high-risk PTCA are unsatisfying, Hemopumps and pCPS were alternatives, although the Hemopump is still under investigation. Our own results on 42 patients with high-risk PTCA demonstrate an acceptable 8.6% hospital mortality rate, however an unsatisfying intermediate survival rate since a complete revascularisation in this subset of patients with extensive coronary disease and, frequently, total vessel occlusion is mostly impossible.

Angioplasty, Balloon, Coronary↗
PubMed1995

Pulmonary and left ventricular decompression by artificial pulmonary valve incompetence during percutaneous cardiopulmonary bypass support in cardiac arrest.

BACKGROUND: In cardiac arrest, use of percutaneous cardiopulmonary bypass support (PCPS) may lead to left ventricular loading, with deleterious effects on the myocardium, and is often accompanied by an increase in pulmonary artery pressure. The present study was designed to assess the potential of artificially induced pulmonary valve incompetency to retrogradely decompress the left ventricle during PCPS in ventricular fibrillation. METHODS AND RESULTS: Studies were performed using a standardized experimental animal model in sheep (n = 12; body weight, 77 to 112 kg). When PCPS was used during fibrillation, an increase in left ventricular pressure (from 21.4 +/- 5.0 mm Hg after 1 minute to 28.4 +/- 9.5 mm Hg after 10 minutes of fibrillation) was observed in all animals, with a simultaneous increase in pulmonary artery pressure in 6 animals, from 15.5 +/- 3.8 to 24.3 +/- 5.4 mm Hg (group A). In these animals, artificial pulmonary valve incompetency, which was induced by a special "pulmonary valve spreading catheter," led to effective decompression of both the pulmonary circulation (decrease in pulmonary artery pressure from 24.3 to 11.3 mm Hg) and the left ventricle (decrease in left ventricular pressure from 30.5 to 17.7 mm Hg). We simultaneously measured a decrease in the myocardial release of lactate (increase in arterial coronaryvenous difference in lactate content from -0.01 to 0.14 mmol/L), demonstrating the myocardial protective effect of the procedure. In contrast, in 6 animals without an increase in pulmonary artery pressure during PCPS (group B), artificial pulmonary valve incompetency did not reduce left ventricular loading, which was probably because of competent mitral valves in these animals. CONCLUSIONS: In case of increasing pulmonary artery pressure during PCPS in cardiac arrest, artificial pulmonary valve incompetency might be a useful tool for effective pulmonary and retrograde left ventricular decompression.

Animals↗
PubMed1994

Mechanical left ventricular unloading during high risk coronary angioplasty: first use of a new percutaneous transvalvular left ventricular assist device.

A new catheter mounted, transvalvular left ventricular assist device has been designed for percutaneous transfemoral access. The device, the Hemopump [14 French (Fr.) outer diameter], is based on a mixed flow rotary pump and is capable of flow rates of 1.5-2.2 l/min. The pump is inserted using a specialized 16 Fr. femoral introducer sheath. The first application of the percutaneous Hemopump in man was performed in two patients with hemodynamic compromise during high risk coronary angioplasty. In these patients, Hemopump support resulted in hemodynamic stabilization (increase in aortic pressure from 60/42 to 87/61 and from 80/60 to 100/70 mm Hg, respectively) and marked left ventricular unloading (decrease in pulmonary capillary wedge pressure from 25 to 10 and from 14 to 10 mm Hg) during balloon inflation. In both patients, percutaneous transluminal coronary angioplasty (PTCA) could be accomplished successfully. Using the system for periods of about 2 hr in each patient, we observed no vascular, hemorrhagic, or embolic complications. In both patients, only a minor increase in both plasma free hemoglobin and lactate dehydrogenase levels was noted. Our preliminary experiences suggest that the percutaneous Hemopump is safe and effective and may be a powerful alternative to other devices used for supported angioplasty.

Aged↗
PubMed1994

Comparison of hemodynamic and Doppler echocardiographic effects of a new low osmolar nonionic and a standard ionic contrast agent after left ventriculography.

The hemodynamic effects of a new nonionic low osmolar contrast agent (iomeprol) during left ventriculography (LC) was compared with a standard ionic contrast agent (meglumine diatrizoate) in a randomized double blind study in 30 patients with suspected coronary artery disease and normal systolic ventricular function. LV diastolic function was assessed by Doppler echocardiographic recording of the transmittal filling curve and by intraventricular tip-manometry before and within 30 sec of the LC. In the group receiving the ionic contrast agent the systolic pressure fell from 126 +/- 23 to 111 +/- 18 mmHg (P < 0.05), and heart rate increased from 64 +/- 9 to 71 +/- 11 min-1 (P < 0.05), while no such effects were observed with the nonionic contrast agent, indicating differences in the vasodilator properties. The latter caused an increase of the peak early Doppler velocity (52 +/- 11 to 62 +/- 14 cm/sec; P < 0.05). After the ionic contrast agent, the effect on the peak early Doppler velocity was less pronounced, probably due to an interaction with the known depressant effect of the increase in heart rate on the early Doppler velocity. In both groups the left ventricular end diastolic pressure was increased from 7 +/- 3 to 10 +/- 4 mmHg. No significant effects on peak-dp/dt and dp/dt were observed in either group. The nonionic contrast agent iomeprol had no significant effect on systolic arterial pressure and heart rate in contrast to the ionic contrast agent, probably due to a less pronounced vasodilator effect. Despite these differences of the global hemodynamic response, there were similar effects of both contrast agents on LV diastolic filling.

Adolescent↗
PubMed1994

Left-ventricular unloading by transvalvular axial flow pumping in experimental cardiogenic shock and during regional myocardial ischemia.

The efficacy of the transfemoral left-ventricular assist device Hemopump (HP; 21 Fr outer diameter) was examined in experiments with adult sheep in two different models of cardiogenic shock (tachycardia shock; ischemia shock), and during ventricular fibrillation. During tachycardia (high frequency pacing-induced; n = 14), HP assist led to a significant increase in cardiac output (from 2.2 to 2.8 liters/min), mean aortic pressure (from 47.6 to 65.6 mmHg), and myocardial perfusion pressure (from 25.5 to 59.0 mmHg). Simultaneously, a normalization of body oxygen-uptake (from 1.4 to 2.5 ml/min.kg), a decrease in myocardial oxygen consumption (from 6.1 to 4.8 ml/min.100 g), and a normalization of myocardial lactate metabolism were observed during HP assist. During regional myocardial ischemia (PTCA balloon occlusion of the proximal LAD (3.5 min; n = 12), HP assist led to significant decrease in LV end-diastolic pressure (from 21.1 to 12.1 mmHg), and increase in diastolic aortic pressure (from 58 to 67 mmHg) resulting in significant increase in coronary perfusion pressure. In the early reperfusion period, myocardial release of both lactate and potassium was significantly lowered with HP assist. During ventricular fibrillation (induced by electrical stimulation; n = 9), HP flow rates decreased from 2.5 (after 10 min) to 2.1 liters/min (after 30 min). Mean aortic pressures simultaneously decreased from 64.0 to 54.6 mmHg. Perfusion conditions were sufficient for maintenance of aerobic myocardial metabolism, but were borderline for peripheral circulation. Our hemodynamic and metabolic data demonstrate beneficial effects of cardiac assist with the Hemopump 21 Fr in both tachycardia-induced severe cardiogenic shock and during acute regional myocardial ischemia.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1994

Need for active left-ventricular decompression during percutaneous cardiopulmonary support in cardiac arrest.

During ventricular fibrillation, myocardial hemodynamic and metabolic effects of percutaneous cardiopulmonary support (PCPS) were analyzed in 11 adult sheep (body weight 77-112 kg). During supported fibrillation, an abrupt increase in left-ventricular pressures with alignment to aortic pressures was observed in 2 animals, which was probably due to spontaneous aortic regurgitation, and resulted in deterioration of coronary perfusion. In 9 animals, left-ventricular pressures rose from 22.9 +/- 4.9 to 31.2 +/- 7.9 mm Hg elevating left ventricular wall stress from 16,750 +/- 8,745 to 28,835 +/- 8,892 dyn/cm2 after 10 min of PCPS-supported fibrillation (mean flow rate 4.5 +/- 0.7 liters/min). Simultaneously, myocardial perfusion pressures decreased from an average of 32.4 +/- 11.7 to 22.3 +/- 9.4 mm Hg and myocardial lactate release was observed. Additional transapical LV venting using a 9-Fr catheter led to a decrease in both LV pressure (to 25.7 +/- 5.3 mm Hg) and wall stress (to 20,612 +/- 7,499 dyn/cm2). Left-ventricular decompression decreased myocardial oxygen consumption (from 5.3 +/- 1.4 to 4.8 +/- 0.9 ml/min.100 g), and reduced myocardial lactate release, which indicates myocardial protection. Protective effects were most pronounced using 12-Fr-, and 21-Fr-venting cannulas (with 21 Fr: decrease in myocardial oxygen consumption to 2.7 +/- 0.6 ml/min.100 g, and reversal of myocardial lactate release to lactate uptake during fibrillation). Conclusions. Hemodynamic and metabolic data clearly demonstrate the deleterious effects of PCPS to the unvented left ventricle during cardiac arrest. The results emphasize the need for active left-ventricular decompression during PCPS in ventricular fibrillation.

Animals↗
PubMed1994

[Mechanical cardiac assist systems in intensive care].

The indications for the use of mechanical cardiac assist-devices are sudden death, cardiogenic shock, severe coronary ischemia and high-risk PTCA. Among the cardiac assist-devices, currently available for cardiologists and cardiac surgeons, are the Intraaortal Balloon Pump (IABP), the implantable turbine-pump, the percutaneous cardiopulmonary support (PCPS), centrifugal pumps which are connected via a thoracotomy and intra- and extrathoracic total artificial hearts. It is easy to position the IABP, which can be continuously used over the course of several days. In the case of cardiogenic shock, the pump should be implanted as soon as possible, in order to facilitate revascularisation procedure in a patient with ischemic heart disease. By this procedures the survival rate of ischemic cardiogenic shock has been raised from 20% to 60%. However, the IABP does not prove supportive in the case of an MI without shock or in high-risk PTCA. The implantable turbine pump (Hemopump TM) is available in 3 configurations, ranging in external size from 14 F to 26 F. Of these, only the 14 F pumps can be implanted percutaneously by a Seldinger technique, whereas the bigger pumps require arteriotomy or thoracotomy for placement. The pump-rates of these systems reach from 2.0 l/min to 4.5 l/min. These pumps are used in high-risk PTCA as well as CABG-surgery without cardiopulmonary support, but are still currently in a test phase. However, at this point, it is still too early to finally evaluate the clinical importance of these systems. The percutaneous cardiopulmonary support (PCPS) has a major advantage over all other assist device systems, as it completely replaces the circulation. Therefore, PCPS is especially indicated in cardiac arrest, because it can be inserted very quickly, even without having to interrupt resuscitation. A second indication is high-risk PTCA, where it can be used also as a stand-by system. A study with 801 patients, investigating the use of this system in high-risk PTCA, resulted in a hospital mortality of 6.9%. In therapy-resistant circulatory arrest, approximately 30% of patients could be saved with this system, provided that there is a very quick access to it, as there is for example in the cardiac cath lab. Centrifugal pumps, which are inserted via a thoracotomy, and artificial hearts have become very important and are now used routinely in cardiac surgery to support patients, who have developed therapy-refractory heart failure, and in transplantation-surgery as "bridging to transplant". These systems, however, bear the complications of hemorrhage and thromboembolism.(ABSTRACT TRUNCATED AT 400 WORDS)

Angioplasty, Balloon, Coronary↗