Mechanical circulatory support with the Impella 5.0 device for postcardiotomy cardiogenic shock: a three-center experience.

AIM: Postcardiotomy cardiogenic shock (PCCS) is associated with high mortality rates, despite full conventional treatment. Although the results of treatment with surgically implantable ventricular assist devices have been encouraging, the invasiveness of this treatment limits its applicability. Several less invasive devices have been developed, including the Impella system. The objective of this study was to describe our three-center experience with the Impella 5.0 device in the setting of PCCS. METHODS: From January 2004 through December 2010, a total of 46 patients were diagnosed with treatment-refractory PCCS and treated with the Impella 5.0 percutaneous left ventricular assist device at three european heart centers. Baseline and follow-up characteristics were collected retrospectively and entered into a dedicated database. RESULTS: Within the study cohort of 46 patients, mean logistic and additive EuroSCORES were 24 ± 19 and 10 ± 4. The majority of patients underwent coronary artery bypass grafting (48%) or combined surgery (33%). Half of all patients had been treated with an intra-aortic balloon pump before 5.0-implantation, 1 patient had been treated with an Impella 2.5 device. All patients were on mechanical ventilation and intravenous inotropes. The Kaplan-Meier estimate of overall 30-day survival was 39.5%. CONCLUSION: Thirty-day survival rates for patients with PCCS, refractory to aggressive conventional treatment and treated with the Impella 5.0 device, are comparable to those reported in studies evaluating surgically implantable VADs, whereas the Impella system is much less invasive. Therefore, mechanical circulatory support with the Impella 5.0 device is a suitable treatment modality for patients with severe PCCS.

A clone of coagulase-negative staphylococci among patients with post-cardiac surgery infections.

Coagulase-negative staphylococci (CoNS) are important causes of hospital-acquired infections such as infections after cardiac surgery. Efforts to reduce these infections are hampered by the lack of knowledge concerning the epidemiology of CoNS in this setting. Forty strains of CoNS collected during the surgical revision of 27 patients operated on between 1997 and 2000 were analysed. Strains were also collected from the ambient air in the operating suite. Their pulsed-field gel electrophoresis (PFGE) characteristics and antibiotic resistance were analysed. Using PFGE 19 of 40 strains from 15 of 27 patients were shown to belong to one clone, and strains from this clone were also isolated from the ambient air. This clone had caused infections throughout the period. Antibiotic resistance did not correlate with PFGE patterns. Using PFGE one clone could be identified that caused 56% of the CoNS infections during this period. A strain from this clone was also found in the air of the operating suite suggesting the origin of the CoNS causing infections was the hospital environment.

Changes in the appearance and treatment of deep sternal infections.

The Department of Thoracic Surgery at the University Hospital, Linköping, Sweden, has actively followed up infectious complications of cardiac surgery since 1989. The aim of this study was to investigate whether changes occurred during the 1990s in the appearance and the management of deep infections. This was done by studying patients undergoing surgical revision of infected wounds. We studied 42 patients during 1990-94 and 49 during 1997-98 (total number of operations in these periods, 3075 and 1646, respectively). Pre-operative and intra-operative variables were recorded for the two patient populations. The proportion of cardiac surgery procedures followed by a surgical revision for an infection in the sternal wound increased between the two periods (1.4% vs. 3.0%). Variables associated with the surgical procedures preceding the infection remained unchanged. In the later period, treatment was started earlier (64 vs. 24 days), and the length of antibiotic treatment was decreased (115 vs. 72 days). The incidence of osteomyelitis of the sternal bone was lower (61% vs. 27%). It appears that as the proportion of patients undergoing surgical revision increased, management of the infections became more effective, with aggressive surgical and antibiotic treatment policies and shorter treatment periods. This indicates that in order to evaluate the overall impact of measures designed to reduce infections after cardiac surgery, not only the incidence of infection needs to be followed up but other factors also need to be taken into account.

Heart rescue in acute left main coronary artery occlusion with CABG using initial retrograde perfusion.

Acute occlusion of the left main coronary artery (LMCA) is a rare and almost invariably fatal condition. Here, we report on heart salvage in two such cases with CABG aided by emergent retrograde reperfusion as the initial operative step. Both cases were extremely unusual. The first patient had twice survived LMCA occlusion; the second also had right coronary artery occlusion. We will also review the literature on acute LMCA occlusion and coronary venous retroperfusion.

Superficial and deep sternal wound complications: incidence, risk factors and mortality.

OBJECTIVES: Sternal wound complications often have a late onset and are detected after patients are discharged from the hospital. In an effort to catch all sternal wound complications, different postdischarge surveillance methods have to be used. Together with this long-term follow-up an analysis of risk factors may help to identify patients at risk and can lead to more effective preventive and control measures. METHODS: This retrospective study of 3008 adult patients who underwent consecutive cardiac surgery from January 1996 through September 1999 at Linköping University Hospital, Sweden, evaluated 42 potential risk factors by univariate analysis followed by backward stepwise multivariate logistic regression analysis. RESULTS: Two-thirds of the 291 (9.7%) sternal wound complications that occurred were identified after discharge. Of the 291 patients, 47 (1.6%) had deep sternal infections, 50 (1.7%) had postoperative mediastinitis, and 194 (6.4%) had superficial sternal wound complications. Twenty-three variables were selected by univariate analysis (P<0.15) and included in a multivariate analysis where eight variables emerged as significant (P<0.05). Preoperative risk factors for deep sternal infections/mediastinitis were obesity, insulin-dependent diabetes, smoking, peripheral vascular disease, and high New York Heart Association score. An intraoperative risk factor was bilateral use of internal mammary arteries, and a postoperative risk factor was prolonged ventilator support. Risk factors for superficial sternal wound complications were obesity, and an age of <75 years. The 30 day mortality was 2.7% for patients without sternal wound complications and 2/291 (0.7%) for all patients with sternal wound complications, 0.5% for superficial sternal wound complications, and 1.0% for deep sternal infections/mediastinitis. The 1 year mortality rate was 4.8% for patients without sternal wound complications and 11/291 (3.8%) for patients with sternal wound complications, 2.1% for superficial sternal wound complications, and 7.2% for deep sternal infections/mediastinitis. CONCLUSIONS: The risk factors found in this study have been detected and reported in previous studies. The predictive ability was stronger though for deep sternal infections/mediastinitis (those needing surgical revisions) than for superficial sternal wound complications. Earlier recognition of sternal wound complications and aggressive treatment have probably contributed to the relatively low mortality rate seen in this study.

Knowledge representation forms for data mining methodologies as applied in thoracic surgery.

Typical ways of disseminating and using results of clinical research are scientific journals and reports. Presentation forms are condensed and comprehensible mainly to the experts following the specific topics. A vast amount of information remains unutilized due to the complex form of presenting the knowledge. Subject of this research is to explore possibilities of representation and also visualization of the results obtained using data mining methodologies. The intention is to formulate more than scientific ways to communicate facts that are of interest for the clinicians, medical students and even patients. Internet technologies as already widely established media support knowledge representation forms such as hypertext documents and structured knowledge components. The "Assist Me" decision support system for surgical treatment of cardiac patients integrates several forms of data mining and representation methodologies. We are showing a feasibility study in which scientific outcomes were forwarded to a broad group of potential users.

Management of patients with end-stage heart disease treated with an implantable left ventricular assist device in a nontransplanting center.

OBJECTIVE: To describe the setup of a left ventricular assist device (LVAD) program in a nontransplanting center. DESIGN: A prospective study from February 1993 to June 1999. SETTING: A university hospital. PARTICIPANTS: Ten patients, 6 men, with a mean age of 44 years (range 16 to 63 years) and with end-stage heart failure resulting from dilated cardiomyopathy (n = 7) or ischemic heart disease (n = 3). INTERVENTIONS: The patients received the TCI (Thermo Cardiosystems Inc, Woburn, MA) Heart Mate implantable assist device. Five patients had a pneumatic device, and 5 had an electric device. All except 1 patient with an electric device had the pump for an extended period. MEASUREMENTS AND MAIN RESULTS: Median time on the ventilator was 6.2 days, and median time in the ICU was 14 days. Significant hemodynamic improvement was observed by echocardiography and invasive monitoring. Milrinone and epinephrine supplemented by prostaglandin E1 were the most commonly used drugs to avoid right-sided heart failure. Nine patients were transplanted after pump therapy of 241 days (median) (range, 56 to 873 days). One patient died because of endovascular infection and septicemia. Infectious complications were frequent, especially when the pump time was extended. CONCLUSIONS: The introduction of an LVAD program in a nontransplanting center can be achieved with good results. Intense collaboration with a transplant center is mandatory. The complication rate increased when treatment times were extended.

Initial tests with a new cardiac assist device.

Before, during, and after cardiac intervention, there is occasionally a need for circulatory support because of hemodynamic deterioration. For this purpose, a new minimally invasive cardiac assist device has been developed, and an early prototype has been studied in a bench test and in three pigs. The pump is a catheter system with a distal motor driven propeller (0-15,000 rpm) surrounded by a cage. The catheter was first tested in a tube in a water bath, where efficiency with respect to pressure generation and flow properties was measured. In the pig experiments, the pump was placed in the descending part of the aorta via a graft, and hemodynamic effects were recorded with three different propellers. The bench tests showed a velocity dependent pressure generation in the tube to the second power of the rpm, and 30 cm of water (> 22 mm Hg) could easily be achieved with all propellers. A pressure dependent flow in the tube was observed, with maximum flows of 20 L at 12,000 rpm and 27 L at 15,000 rpm. In the animal experiments, there was a velocity dependent mean pressure difference across the propeller, with up to 48 mm of mercury for the biggest propeller. An increase in cardiac output in all of the pigs was observed as well as a drop in pressure in the proximal part of the aorta. This study demonstrates the efficiency of this new device in vitro and in vivo. Hemodynamic changes are pronounced and are related to the speed and size of the propeller.

HeartMate left ventricular assist device as bridge to heart transplantation.

BACKGROUND: Because of the limited supply of donor hearts, prospective recipients continue to die while on the waiting list for heart transplantation. Use of long-term mechanical circulatory support devices as a bridge to transplantation may reduce this mortality. However, with the present state of technology, continued clinical evaluation of the various long-term, mechanical circulatory support devices available is mandatory. METHODS: Sixteen patients were bridged with the HeartMate left ventricular assist device (LVAD) to heart transplantation for New York Heart Association functional class IV cardiac failure. Twelve pneumatic and six electric devices were used. The mean cardiac index and the mean pulmonary vascular resistance of the patient cohort were 1.71 x min(-1) x m(-2) and 3.1 Wood units, respectively. RESULTS: The mean LVAD support time per transplanted patient was 237 days, with a cumulative LVAD support time of about 7.2 years. Bleeding was the main operative and postoperative complication. Two patients suffered from neurologic complications and there were two major incidents of device malfunction. Twelve patients (75%) now have received a transplant, 3 (19%) are awaiting a transplant, and in 1 patient (6%), the device was explanted after spontaneous left ventricular recovery. Eleven of the 12 patients who received a transplant are alive and doing well. The HeartMate LVAD gave adequate circulatory support over extended periods of time and reversed the vital organ dysfunction. Since the start of the LVAD program, only 1 patient has died on our heart transplantation waiting list, compared to nine deaths in the 2 preceding years. CONCLUSIONS: The HeartMate LVAD bridge to heart transplantation can be performed with low post-LVAD implantation and posttransplantation mortality and offers 1- and 2-year posttransplantation actuarial survival rates comparable to those for nonbridged heart transplant recipients.

Postoperative management of patients with Hemopump support after coronary artery bypass grafting.

BACKGROUND: In this study, we describe postoperative monitoring, pharmacologic therapy, and hemodynamic responses in patients receiving Hemopump support after postcardiotomy heart failure. METHODS: The Hemopump was used in 24 patients with severe left ventricular dysfunction after coronary artery bypass grafting. RESULTS: Fourteen patients (58%) were weaned from the Hemopump. Low to moderate doses of a combination of catecholamines, phosphodiesterase inhibitors, vasodilators, and vasoconstrictors were required to optimize Hemopump function and left ventricular unloading. Mean arterial blood pressure, mixed venous oxygen saturation, and urinary output were the most important therapy guidelines. CONCLUSIONS: Together with our clinical protocol, the Hemopump effectively unloaded the failing ventricle while maintaining vital-organ perfusion. Doses of vasoactive drugs could be kept low. This approach to treatment provides good conditions for recovery of the stunned myocardium.

Hemopump treatment in patients with postcardiotomy heart failure.

BACKGROUND: This study examined the use of the Hemopump to treat low cardiac output syndrome after cardiopulmonary bypass. METHODS: We used the Hemopump temporary cardiac assist system in 29 patients with severe left ventricular dysfunction after open heart operations from September 1991 to November 1994. RESULTS: Five patients were excluded from the study due to initial patient/device-related problems. Ten patients died in the operating room or early during the stay in the intensive care unit due to progressive biventricular failure. Fourteen patients (58.3%) were weaned from the device, and all of them were later discharged. In a subgroup of patients (54%) in whom we had a more aggressive approach for early insertion of the pump, the survival rate was 85%. Preoperative Higging risk score was significantly related to survival. CONCLUSIONS: The Hemopump can effectively unload a failing left ventricle with preservation of multiorgan perfusion. A minor decrease in kidney function was observed in most patients, but none of the surviving patients needed hemodialysis. One patient required a short period of peritoneal dialysis to get rid of fluid overload. Hemolysis or platelet dysfunction was not a clinical problem.

A comparison of propofol and isoflurane anaesthesia: the need for ephedrine and glycopyrrolate.

Sixty patients, ASA I-III, presenting for elective colonic surgery were studied to assess the stability of blood pressure and heart rate during anaesthesia with three equally potent anaesthetic techniques. Patients in group I (n = 20) received thiopentone induction, isoflurane and nitrous oxide; patients in group II (n = 20) received total intravenous anaesthesia with propofol; and patients in group III (n = 20) received intravenous propofol supplemented with nitrous oxide. Fentanyl and vecuronium were used in all three groups. The depth of anaesthesia was judged on clinical signs of adequate anaesthesia. Episodes of bradycardia (heart rate < 50 beats min-1), tachycardia (heart rate > 90 beats min-1), hypotension (mean arterial pressure > or = 30% below pre-operative blood pressure) or hypertension (mean arterial pressure > 30%, or systolic blood pressure > 15 mmHg, above pre-operative value) were recorded when lasting > 5 min. Any use of ephedrine or glycopyrrolate given to correct hypotension or bradycardia was documented: In group II, significantly more patients were given ephedrine (P < 0.01) to treat hypotension. The drug was administered after intubation but before skin incision in the majority of cases (9/11). Glycopyrrolate was given to significantly more patients in group III (P < 0.025) to treat bradycardia, and in 21 of a total of 34 patients given glycopyrrolate it was administered before surgery. With the use of these additional drugs, there were no differences in the number of patients with 5 min episodes of hypotension, hypertension, tachycardia or bradycardia.(ABSTRACT TRUNCATED AT 250 WORDS)

The Linköping-Lund surgical experience with the HeartMate left ventricular assist system.

Four transplant candidates fulfilling the Food and Drug Administration criteria for a permanent left ventricular assist device received a pneumatic HeartMate system as a bridge to heart transplantation. All patients survived and were fully rehabilitated at the time of transplantation, which was carried out 2 to 6 months after the initial operation. There were no major complications associated with the procedures. We are impressed by the effectiveness and safety of the device.

Coronary artery operation supported by the Hemopump: an experimental study on pig.

Twelve pigs undergoing coronary artery bypass grafting had the Hemopump to decompress the heart and as circulatory support. The pigs also were given a short-acting beta-blocker, esmolol, to make the heart flaccid. Extracorporeal circulation was not used. During Hemopump support, a bolus dose of 0.5 to 5 mg/kg of esmolol was given before incremental titration steps from 100 to 600 micrograms.kg-1.min-1 over 15 to 20 minutes. The internal thoracic artery was sutured to the distal part of the left anterior descending artery. The Hemopump was withdrawn to the aorta after a weaning period of 20 to 30 minutes. Seven of 12 pigs went through the whole procedure and the Hemopump was weaned off without complications. Five animals died due to right ventricular failure in association with esmolol administration. There was a big interindividual difference in esmolol dose-response curves in the surviving animals. No significant differences in the hemodynamic variables were observed during the experiment. The Hemopump in combination with a short-acting beta-blocker could be an alternate way of performing coronary artery bypass grafting in selected patients.

Coronary artery operation with support of the Hemopump cardiac assist system.

Five patients with one- or two-vessel disease had one to three bypass grafts using the Hemopump cardiac assist system instead of cardiopulmonary bypass to decompress the heart and as circulatory support. In addition, the short-acting beta-blocker esmolol was given as a bolus and stepwise titrated to make the heart flaccid and facilitate operation. All patients had a 24F Hemopump placed into the left ventricle. The patients were given 7,500 U of heparin. Average time on Hemopump support was 56 minutes. All patients went through the procedure uneventfully. Thirty minutes after pump removal all patients were back to baseline hemodynamic values. None of the patients needed blood transfusion. No postoperative renal impairment was seen. This method has great potential and could avoid the drawbacks associated with cardiopulmonary bypass and cardioplegic arrest. Careful evaluation in randomized studies is the next step.

Use of vectorcardiography in determination of the left ventricular muscle mass.

Many studies have investigated different ECG and vectorcardiographic (VCG): criteria for diagnosis of left ventricular hypertrophy (LVH). In some investigations VCG was more sensitive than ECG in this respect. This study was performed to elucidate whether it is possible also to determine the degree of LVH using VCG. Eighty cardiovascularly healthy subjects aged 15-39 were investigated with ECG, VCG (Frank system) and echocardiography. The echocardiographic left ventricular (LV) mass has been shown by others to correlate closely to the anatomical and the angiographically determined LV mass and was used as reference standard. Thirty-eight of the subjects were endurance sportsmen and had a LV mass above standard reference limits. The measured ECG variables were R-amplitude in a VL, I, V5, V6, S-amplitude in V1 and SV1 + RV5/V6 and the VCG variables were QRS spatial area and circumference and left maximal spatial vector. The sensitivity and specificity of single criteria tested were similar for ECG and VCG in the quantitative determination of LVH. The correlations between ECG-amplitudes and the magnitude of the LV mass were weak. The correlations were higher with the VCG-variables, QRS spatial circumference being superior to the others, but not good enough to permit an estimation of the LV mass in individual subjects. In conclusion, normal VCG variables were highly specific for a normal LV mass but in individuals with LVH, VCG was not useful for the estimation of the LV mass.