Hemodynamic Performance and Clinical Consequences of Aortic Valve Replacement with 21-mm Sized Pericardial Bioprostheses

BACKGROUND

Aortic valve replacement (AVR) with a 21-mm sized bioprothesis is still discussed controversially. Since better results have been reported for pericardial valves, the aim of the current study was to analyze the hemodynamic performance as well as clinical parameters in our patients and to compare pericardial and standard porcine valves in particular.

METHODS

342 patients underwent AVR with a bioprosthesis between 1987 and 2000. A 21 mm prosthesis was used in 39 patients (group S), while 303 patients received at least a 23-mm sized valve (group L). Group S was further divided into 19 patients with a pericardial valve (group S1) and 20 patients with a standard porcine valve (group S2). The hemodynamic and clinical parameters were studied in all three groups.

RESULTS

The peak and mean transprosthetic gradients were significantly lower in the pericardial group than in the porcine group, particularly between patients with 21 mm valves (peak/mean: S1: 24 +/- 9/20.8 +/- 6.5 mm Hg vs. S2: 38 +/- 15/33 +/- 9 mm Hg, p < 0.05) at discharge. We could also observe that the peak transprosthetic gradient 7 days postoperatively was not significantly higher in patients with a 21 mm pericardial valve compared to group L patients. Comparing clinical parameters, we found significantly more cerebral ischemic events, a prolonged mechanical ventilation, a higher mortality and a longer stay in hospital in the group S2 compared to the group S1.

CONCLUSION

The current study shows that pericardial valves perform well, particularly in patients with small aortic roots. Postoperative hemodynamics and clinical results were better than for comparable standard porcine valves. As the outcome of patients with a 21 mm pericardial valve was no worse than that in patients with bigger valves, enlarging procedures for the aortic root are not necessary in the majority of these patients.

Neurological Complications After Cardiac Surgery: Risk Factors and Correlation to the Surgical Procedure

OBJECTIVE

The aim of our study was to analyze risk factors for neurological complications in a group of patients undergoing cardiac operations.

METHODS

We analyzed 783 consecutive patients undergoing cardiac surgery in 2001. Group I consisted of 582 patients with a CABG procedure, group II patients underwent a single valve replacement (n = 101), group III had a combined procedure (CABG + valve) (n = 70), and group IV patients underwent multi-valve procedure (n = 30). Forward stepwise multiple logistic regression analysis was used for statistical evaluation of independent risk factors for neurological complications (reversible deficits and strokes).

RESULTS

The incidence of perioperative neurological problems was 1.7 % in the CABG group, 3.6 % in group II, 3.3 % in group III, and 6.7 % in group IV. With multivariate analysis we could identify various parameters as independent risk factors: previous neurological events, advanced age, and the time of aortic cross-clamping correlated with the incidence of perioperative neurological complications. In addition, we found a predictive value for preoperative anemia, the number of bypasses, an ejection fraction < 0.35 and for insulin-dependent diabetes mellitus. The duration of extracorporeal circulation and the fact of an re-operation could not be identified as risk factors.

CONCLUSION

Our results show that type of surgery, symptomatic cerebrovascular disease, advanced age, diabetes mellitus, and probably aortic atheroma represent the most important risk factors for neurological complications. After preoperative consideration of the individual risk of each patient, neuroprotective interventions (arterial line filtration, alpha-stat management) and pharmacological neuroprotection may offer an improved outcome to some of these "high-risk" patients.

Combined cardiothoracic surgery and interventions of the para/thyroid gland. A rare clinical cooperation

OBJECTIVE

Simultaneous cardiothoracic and general surgical interventions are still a matter of controversy. We investigated the question whether combined open heart surgery or thoracic surgery and interventions of the parathyreoid respectively thyroid gland may be helpful for the patients.

PATIENTS AND METHODS

The records of six patients (age range: 29-78 years) undergoing simultaneous cardiothoracic and para-/thyroid interventions were examined. Cardiothoracic surgery consisted in three patients of coronary artery bypass grafting, in one of aortic valve replacement, in one of thymus resection and finally in one of resection of a mediastinal Hodgkin's lymphoma. In combination with these procedures three patients underwent a subtotal goiter resection, two patients had a resection of a parathyroid adenoma and one patient underwent a right-sided hemithyroidectomy.

RESULTS

One patient died in the early postoperative course due to global myocardial failure on the base of preoperatively existing reduced left ventricular function. The other postoperative courses were uneventful. The duration of operation was between 165 and 687 min, perfusion time in case of open heart surgery was between 92 and 311 min, ischemic time ranged from 45 to 62 min. The length of hospital-stay ranged from 9 to 26 days. The postoperative follow-up showed all five patients to be in a satisfactory cardiovascular condition. There were no signs of recurrence of either para-/thyroid or Hodgkin's disease.

CONCLUSIONS

The postoperative course does not indicate an increased number of complications, although the total duration of operation and anesthesia is prolonged. Thus we conclude that simultaneous cardiothoracic and endocrine surgery of the para-/thyroid gland can be performed with acceptable risk in cases of preoperative low-risk assessment.

Mechanical assist devices as bridging systems to transplantation: A current review, possible risks, and perspectives

Mechanical circulatory support is of increasing interest because of its considerable demographic importance concerning myocardial failure and because of stagnant transplantation volumes. This study offers an overview of the present state of the art. Institutions with a mechanical circulatory assist program usually dispose of a decision chart for the various systems. There are devices with intra- or extracorporeal pump positions and with long- or short-term application. The various possibilities of mechanical circulatory assistance are presented, along with their technical properties, indications, and results. Currently, the application is concerned with technical reliability and limited biocompatibility with thrombembolic, neurological, and infectious complications. With some further developments, the present state of the art is supposed to enable a widespread application as bridging systems and as long-term therapy of heart failure within the next few years.

Reverse remodeling by net cardioplasty in a model of dilated cardiomyopathy: results of an animal study

AIM

End-stage heart failure is a growing clinical problem with only a few satisfactory therapeutical options. Dilated cardiomyopathy (DCM) is associated with a progressive decline in cardiac function. Our hypothesis was to arrest this worsening of cardiac function by mechanically containing the dilated heart with a special net.

METHODS

In 16 pigs (50+/-7 kg) DCM congestive heart failure was initiated by rapid ventricular pacing (220 b/m). In series 1 (n=8) a polyester net was placed around both ventricles before pacing was induced, whereas in series 2 (n=8) ventricular wrapping was performed when DCM was established.

RESULTS

Comparing hemodynamic data before re-operation of group 11-animals, the decrease of CO and dp/dt(max) was significantly lower in series 1 than in series 2 compared to the baseline values before pacing (CO: series 1:-22.6+/-3.3%, series 2:-52.4+/-6.4%, p<0.05; dp/dt: series 1: +16.4+/-2.8%, series 2: -51.5+/-5.9%, p<0.05). In series 2, after net implantation, we could furthermore show that deterioration of the animal stopped and hemodynamic data improved significantly in the following 2 weeks (CO: +62.9+/-10.5% and dp/dt +37.0+/-6.8%).

CONCLUSION

Ventricular containment with a polyester net seems to be a therapeutic option in cardiac insuffiency caused by ventricular dilation. This cardioplasty induced a reverse remodeling of the dilated hearts with a significant improvement in diastolic and systolic ventricular function.

Determination of the coronary flow reserve of the LAD in patients with HOCM using the intracoronary Doppler catheter

OBJECTIVE

Hypertrophic obstructive cardiomyopathy (HOCM) is still a serious problem that is characterized by an increasing hypertrophy of the cardiac muscle. The aim of this study was to investigate the hypothesis whether in HOCM the coronary flow reserve in the left anterior descending artery (LAD) is influenced by pharmacologic stimulation or stimulation using a pacemaker.

PATIENTS AND METHODS

The study was carried out in 15 patients (6 male, 9 female) with the typical echocardiographic signs of HOCM without coronary artery disease. Using an intracoronary Doppler catheter the average peak velocity and the absolute coronary flow reserve were determined in the proximal, medial and distal part of the LAD under influence of Papaverine, Substance P and under pacemaker stimulation. The coronary square plane was calculated angiographically under the influence of Substance P. Moreover, the retrograde flow was studied and the coherence between the increase of the coronary square plane and the coronary flow reserve were investigated. For statistical analysis the mean value, the standard error of the mean, Spearman's correlation coefficient and the t-test were calculated.

RESULTS

Under pharmacologic stimulation higher values in the average peak velocity were observed compared to pacemaker stimulation. A retrograde flow was observed in 8 out of 10 patients. The coronary flow reserve was higher under pharmacologic influence than under pacemaker stimulation. A coherence between the increase of the coronary square plane and the coronary flow reserve was not found.

CONCLUSIONS

So far, from the published data concerning the characteristics of coronary flow in HOCM patients, only the retrograde flow was reproducible in our patient group. However, a decrease of the coronary flow reserve compared to a healthy control group of the literature could not be observed. Nevertheless ischemia in the subordinate vessels and on the base of microcirculation cannot be excluded.

Comparison of complete and incomplete revascularization in CABG-patients with severely impaired left ventricular function (LVF)

OBJECTIVE

CABG-procedures in patients with depressed LV-ejection fraction (LVEF) may still cause complications. In patients with severely impaired LVEF, it is particularly unclear whether a complete revascularization (CR) leads to a better outcome than the possible advantage of a short period of ischemia. This may be reached by a possibly incomplete revascularization (ICR).

METHODS

In our department, 263 patients with LVEF < 30% underwent a CABG-procedure between 1996 and 2000. Patients were divided into two groups with regard to their revascularization: group A patients (n = 158) received all grafts that were thought to be necessary according to preoperative angiography, whereas in group B (n = 105) at least one graft could not be realized.

RESULTS

Mean number of grafts per patient was 3.59 +/- 0.58 in group A and 2.92 +/- 0.47 in group B (p < 0.05). Intraoperatively, 33% of group A patients needed catecholamines, compared to 48% in group B (p < 0.05). IABP was used more often in group B (n = 7 compared to n = 3 in group A) (p < 0.05). Postoperatively, there were also significant differences: duration of mechanical ventilation (A: 12.1 +/- 3.4 h; B: 20 +/- 5.2 h) (p < 0.05) and stay on ICU (A: 3.0 +/- 0.6 days; B: 4.2 +/- 0.6 days) (p < 0.05) were significantly prolonged in group B patients. Six patients from group B died during hospitalization (6%), compared to five from group A (3.2%) (p < 0.05).

CONCLUSIONS

In patients with a severely depressed LVEF, complete revascularization improves the outcome after CABG-procedures. A prolonged time of intraoperative ischemia and CPB can be accepted to realize an effective revascularization.

Concomitant CABG-procedures in elderly patients undergoing aortic valve replacement

OBJECTIVE

Preoperative coronary angiography in elderly people referred to the hospital for aortic valve replacement (AVR) often shows additional significant stenoses of the coronary arteries (CAD). The benefit of concomitant coronary artery bypass grafting (CABG) in these patients is still discussed controversially. By some authors, an isolated AVR in elderly patients with additional CAD is even described to have a better outcome.

PATIENTS AND METHODS

We analyzed 283 patients (> or =75 years), undergoing AVR with or without concomitant CABG-procedures. We particularly analyzed those patients who were operated with an isolated AVR in spite of preoperatively known CAD. There were 166 patients in the AVR group (gr. A) and 117 patients in the AVR+CABG group (gr. AC). 51 of these patients with isolated AVR were preoperatively known to have an additional CAD (stenoses <60%) (gr. A2), whereas 115 patients of group A only suffered from an isolated aortic valve disease (gr. A1).

RESULTS

Comparing group A and AC, we found a significantly prolonged mechanical ventilation in group AC (22.3+/-5.3 hours vs 10.1+/-1.9 h in gr. A, p<0.05) and a longer stay on the ICU. The incidence of severe postoperative complications and the in-hospital mortality were comparable. In group A2 we could differ between stenoses of the LAD (n=19) and of the right coronary or circumflex artery (n=32). The decision not to bypass a stenosis of the LAD caused a significantly worse outcome of these patients compared to group AC. Ignoring stenoses of the RCA or RCx was not correlated with an impaired postoperative result.

CONCLUSIONS

With our results we could not identify concomitant CABG as a predictor of poor surgical outcome in elderly patients with AVR. We could even show that an additional bypass grafting of moderate stenoses of the LAD is important for a good outcome of these patients. Comparable stenoses in the right coronary or circumflex artery may be ignored with the advantage of a shorter period of intraoperative ischemia and the possibility of a secondary catheter intervention.

EuroSCORE as a predictor for complications and outcome

OBJECTIVE

The purpose of this study was to evaluate the usefulness of EuroSCORE in terms of prediction of the outcome as a result of preoperative information in a cohort of patients.

METHODS

We analyzed the data from 751 patients treated between Jan 1 and Dec 31, 1998. We used contingency tables and applied methods of discriminant analysis for the evaluation.

RESULTS

Compared to the 14.799 patients from whose data the EuroSCORE system had originally been derived [1,2], we had a smaller portion of patients in the low-risk group (24.5% vs. 30.6%), a comparable portion of patients in the medium-risk group (42.2% vs. 40.5%) and a higher proportion of patients in the high-risk group (33.2% vs. 29.0%). This difference in the risk distributions was highly significant (p < 0.001). The application of the EuroSCORE system showed that deaths only occurred in the high-risk group in our hospital. We had 36 deaths amongst the patients, which gives an overall mortality rate of 4.9% and a mortality rate of 1.6% in the medium-risk group and of 12.4% in the high-risk group. The discriminant analysis showed that with the EuroSCORE as single predicting variable - virtually all survivors were classified correctly (giving a specificity of 99.0%). The sensitivity was rather low at only 25%; however, this means that many of the high-risk patients in our clinic survived. The total misclassification rate, however, was 12.7%. Additionally, we found that a higher score value predicts a significantly higher probability for perioperative complications and also results in significantly increased average times for the bypass and total time for surgery.

CONCLUSION

The EuroSCORE is a valuable score system for the prediction of the overall outcome of patients following open heart surgery, and is easy to use. As far as perioperative complications are concerned, however, some specifications seem desirable.

Predictors of homologous blood transfusion for patients undergoing open heart surgery

OBJECTIVE

It has become very important to avoid homologous blood transfusions in today's cardiac surgery. We performed a retrospective analysis to find out preoperative factors to predict the risk for transfusion of red-cell concentrate in cardiac surgery.

METHODS

This study included 400 consecutive patients undergoing coronary artery bypass grafting. We also included emergency (4 %) and re-operations (8 %). We tried to find out predictive factors for the need of transfusion of red-cell concentrate on the base of logistic regression coefficient and the odds ratio. We looked at the following factors as predictors of transfusion risk: left ventricular ejection fraction < 0.35, age over 70 years, preoperative hemoglobin < 11 g/dl, insulin-dependent diabetes (IDDM), emergency operation, female sex, impaired renal function (creatinine > 1.6 mg/dl), and re-operation.

RESULTS

In our group, 132 (33 %) patients received transfusion during hospitalization, while 268 (67 %) did not. On average, 2.2 +/- 0.68 units of red-cell concentrate were transfused per patient. In addition, we found a predictive value for transfusion for the following parameters: age > 70 years, preoperative hemoglobin < 11 g/dl, re-operation and ejection fraction < 0.35. We could not find any significantly increased blood transfusion risk in female cases, insulin dependent diabetes mellitus, or impaired renal function.

CONCLUSIONS

We could show that there is normally no need for blood transfusion in (2/3) of the patients in cardiac surgery according to this study's results. Furthermore, it was obvious that some patient variables can be used predict the risk for perioperative transfusion. Based on these results, the prophylactic administration of aprotinin or the use of a cell saver could be useful in selected patients.

Elastase release following myocardial ischemia during extracorporeal circulation (ECC) -- marker of ongoing systemic inflammation?

BACKGROUND

'Post-Perfusion Syndrome' (PPS) after cardiopulmonary bypass (CPB) is known to be evoked by inflammatory reactions. The hypothesis of a pathogenetic role for the neutrophil granulocytes in this inflammation would be strengthened if elevated concentrations of a neutrophil product such as elastase could be demonstrated, particularly in case of a PPS or a systemic inflammatory response syndrome (SIRS).

METHODS

In a randomized prospective double-blind study, 40 patients undergoing aortocoronary bypass grafting (CABG) were divided into 4 groups of 10 patients each. One group served as the control group, one received prostacyclin (PGl 2 ), the third group was substituted with high-dosed aprotinin and the last group was treated with a combination of PGl 2 and aprotinin. 6 blood samples were taken from every patient perioperatively, and plasma elastase (PE), procalcitonin (PCT), C 1 -esterase inhibitor (CEI) and parameters of coagulation and fibrinolysis were determined.

RESULTS

Levels of elastase increased significantly in all intra- and postoperative blood samples compared to the preoperative baseline values (< 30 microg/l, p < 0.05). The elastase release was even more pronounced in the control and aprotinin group (170 +/- 23 microg/l; 175 +/- 14 microg/l during ECC) compared to patients who received prostacyclin (142 = 21 microg/l, p < 0.05). Duration of myocardial ischemia could be directly correlated to elastase levels at the end of CPB. 10 of the 40 patients suffered postoperatively from a PPS or a SIRS; in these patients, elastase levels at the end of CPB were significantly higher (188 +/- 26 microg/l vs. 138 +/- 22 microg/l, p < 0.05). Immediately after the operation, these 10 patients also showed significant changes in the cascades of coagulation and fibrinolysis resulting in a hypercoagulatory state. Levels of PCT and CEI did not change significantly during and after ECC.

CONCLUSIONS

Our results indicate that CPB initiates an elastase release that can be suppressed by prostacyclin. Increased intraoperative elastase levels in patients with PPS show that elastase may be an indicator of ongoing systemic inflammation, possibly causing complications due to a hypercoagulatory state. Myocardial ischemia seems to be one reason for this elastase release. It can be speculated that early PGl2-infusion could be a therapeutic option in inflammatory diseases caused by ECC.

Heart-type fatty acid binding protein (hFABP) in the diagnosis of myocardial damage in coronary artery bypass grafting

OBJECTIVES

Heart-type fatty acid binding protein (hFABP) is an intracellular molecule engaged in the transport of fatty acids through myocardial cytoplasm and has been used as a rapid marker of myocardial infarction. However, its value in the evaluation of perioperative myocardial injury has not yet been assessed.

METHODS

32 consecutive patients undergoing coronary artery bypass grafting were included in a prospective, randomized study using standardized operative procedures and myocardial protection. Three patients with perioperative myocardial infarction were added. Serial blood samples were taken preoperatively, before ischemia, 5 and 60 min after declamping, 1 and 6 h postoperatively and on postoperative days 1, 2 and 10 and were tested for hFABP, creatine kinase isoenzyme MB (CKMB) and troponin I (TnI).

RESULTS

Hospital mortality was zero. The kinetics of the biochemical parameters revealed a typical pattern for each marker. In routine patients, hFABP levels peaked as early as 1 h after declamping, whereas CKMB and TnI peaked only 1 h after arrival in the intensive care unit. Patients with perioperative infarction displayed peak levels some hours later in all marker proteins. Peak serum levels of hFABP correlated significantly with peak levels of CKMB (r=0.436, P=0.011) and TnI (r=0.548, P=0.001), indicating the degree of myocardial damage.

CONCLUSIONS

hFABP is a rapid marker of perioperative myocardial damage and peaks earlier than CKMB or TnI. The kinetics of marker proteins in serial samples immediately after reperfusion is more suitable for the detection of perioperative myocardial infarction than a fixed cut-off level.

Does the time of resternotomy for bleeding have any influence on the incidence of sternal infections, septic courses or further complications?

BACKGROUND

Former studies on sternal wound infections indicate predisposing factors like diabetes, obesity, use of bilateral internal mammary grafts, impaired renal function and reoperation. We wanted to evaluate whether the time of resternotomy for postoperative bleeding has any influence on the development of a sternal wound infection and other complications.

METHODS

In our department, 12,315 patients underwent median sternotomy for cardiac surgery between 1987 and 1998. We analyzed the clinical data of all patients which were reoperated on for postoperative bleeding, especially patients with subsequent operations caused by sternal wound infections. All data were compared by T-test respectively chi2-test, and p<0.05 was regarded as significant.

RESULTS

406 of the 12,315 patients were re-explored because of postoperative bleeding (3.3%). 57 (14%) of these patients died in the postoperative period of non-infectious complications. The remaining patients were divided into two groups: Group A (286 patients) (70.4%) did not suffer from any sternal wound complications, where as group B patients (n = 63) (15.6%) needed subsequent surgery due to sternal infection. There were no significant differences in either concerning age, clinical data and first operation. All patients had an average blood loss of 223 ml/hr. The time before re-operation for bleeding was 5.3+/-1.7 hours in group A compared to 11.1+/-4.2 hours in group B (p<0.05). A significant delay of reoperation for bleeding could also be found for patients with postoperative septic complications (ø: 5.2+/-1.9 hours, +: 12.9+/-5.2 hours), renal failure, mechanical ventilation >48 hours and a stay in hospital >20 days.

CONCLUSIONS

Early reoperation for postoperative bleeding decreases the number of subsequent complications, e.g. sternal wound infections, septic complications and prolonged mechanical ventilation.