TAVI versus SAVR in intermediate-risk patients with severe aortic stenosis and chronic kidney disease: a matched comparison in a subcohort from the GARY registry

Background

According to American and recent European guidelines, both transcatheter aortic valve implantation (TAVI) and surgical aortic valve replacement (SAVR) may be used to treat severe aortic stenosis in a subgroup of patients with intermediate surgical risk, in spite of slight differences in recommended age limits (ACC/AHA: 65–80 years and ESC/EACTS: <75 years). A shared therapeutic decision is made with the patient, based on a heart team assessment. For this, individual factors should be taken into account. Concomitant chronic kidney disease (CKD) is a prognostic factor in such patients, and CKD stage ≥3a and ≥3b has been shown to be a significant independent risk factor for SAVR and TAVI, respectively.

Purpose

To compare TAVI vs. SAVR outcomes in a subgroup of patients for whom both therapies could possibly be considered according to current guidelines.

Methods

The large nation-wide German Aortic Valve Registry (GARY) includes data from patients treated with TAVI or SAVR. A subcohort of patients from GARY with intermediate surgical risk (age ≤80 years, STS-score 4–8) and moderate-to-severe chronic kidney disease (CKD stages 3a, 3b, and 4) was selected. A matched analysis of 704 patients undergoing TAVI and 374 undergoing SAVR was carried out using a propensity score method. Primary endpoint was 1-year survival. Clinical complications and specifically the need for postprocedural new-onset dialysis were secondary endpoints.

Results

TAVI and SAVR showed similar survival results at 1 year in a Kaplan-Meier analysis (HR [95% CI] for TAVI: 1.271 [0.795,2.031], p=0.316). Despite a numerically higher post-procedural short-term survival in TAVI patients and a numerically higher 1-year survival in SAVR patients, such differences did not reach statistical significance (96.4% vs. 94.2%, p=0.199, and 86.2% vs. 81.2%, p=0.316, respectively). In weighted analyses, need for permanent pacemaker, vascular complications, and moderate-to-severe valvular regurgitation were significantly more common with TAVI, whereas patients undergoing SAVR had significantly higher rates of myocardial infarction, and transient ischaemic attack, needed more transfusions for bleeding, and had a significantly longer intensive care unit stay and overall hospital stay. The need for new-onset dialysis for a limited time was more common after SAVR (p<0.0001); however, very few patients required chronic dialysis either after TAVI or after SAVR.

Conclusion

In a matched analysis of intermediate-risk patients with severe aortic stenosis and a concomitant moderate-to-severe CKD, for whom both TAVI and SAVR could possibly be considered, both approaches showed excellent and comparable results.

Funding Acknowledgement

Type of funding sources: Other. Main funding source(s): The registry receives financial support in the form of unrestricted grants by medical device companies (Edwards Lifesciences, JenaValve Technology, Medtronic, Sorin, St. Jude Medical, Symetis S.A.).In addition, there is unrestricted support by funding statisticians by the DZHK (Deutsches Zentrum für Herz-Kreislaufforschung).

Clinical outcomes after surgical or transcatheter aortic valve replacement in patients with chronic kidney disease: an analysis in 29 893 patients from the German Aortic Valve Registry

Background

Chronic kidney disease (CKD) is a key risk factor in patients undergoing transcatheter aortic valve implantation (TAVI) or surgical aortic valve replacement (SAVR).

Purpose

We analyzed the impact of eGFR and different stages of chronic kidney disease (CKD), on short- and mid-term survival in patients undergoing TAVI or SAVR.

Methods

Data from 29893 patients enrolled in the German Aortic Valve registry (GARY) from January 2011 to December 2015 receiving TAVI (n=12834) or SAVR (n=17059) at 88 sites were included. The impact of renal impairment, as measured by eGFR and CKD stages, was investigated. The primary endpoint was 1-year cumulative all-cause mortality. A propensity score method was used to compare TAVI vs. SAVR in patients with intermediate risk and mild-to-moderate renal disease being eligible for both therapies.

Results

Higher CKD stages were significantly associated to lower in-hospital, 30-day- and 1-year survival rates. Both TAVI- and SAVR-treated patients in CKD 3a, 3b, 4, and 5 stages showed significant and gradually increasing HR values for 1-year all-cause mortality. The same trend persisted in multivariable analysis, although HR values for CKD 3a and 5 did not reach significance in TAVI patients, whereas CKD 4+5 did not reach statistical significance in SAVR. Likewise, eGFR as a continuous variable was a significant predictor for 1-year mortality, with the best cut-off points being 47.4 mL/min/1.73 m2 for TAVI and 59.8 mL/min/1.73 m2 for SAVR. Significant 8.6% and 9.0% increases in 1-year mortality were observed for every 5-mL reduction in eGFR for TAVI and SAVR, respectively. No significant differences in survival were found between TAVI and SAVR in a matched group of intermediate-risk patients potentially eligible for both therapies (HR [(95% CI] for TAVI vs SAVR 1.24 [0.76, 2.02], p=0.240).

Conclusions

CKD≥3b and CKD≥3a is an independent major risk factor for mortality in patients undergoing TAVI and SAVR, respectively. In the overall population of patients with severe aortic stenosis, an appropriate stratification based on CKD substage may contribute to a better selection of patients suitable for such therapies. TAVI and SAVR appear to achieve similar survival rates in intermediate-risk patients with moderate-to-severe renal dysfunction.

Funding Acknowledgement

Type of funding source: Private grant(s) and/or Sponsorship. Main funding source(s): Unrestricted grants by medical device companies (Edwards Lifesciences, JenaValve Technology, Medtronic, Sorin, St. Jude Medical, Symetis S.A.). Unrestricted support by funding statisticians by the DZHK (Deutsches Zentrum für Herz-Kreislaufforschung).

Influence of radiofrequency energy on polypropylene sutures in atrial tissue

OBJECTIVE

Bipolar radiofrequency (RF) ablation is an established technique for the surgical treatment of atrial fibrillation. To create complete lesion sets, the bipolar device has to be partially inserted into the heart via a purse-string suture, which is subject to heat damage. We investigated the influence of RF ablation on the structure and function of polypropylene sutures.

METHODS

Six polypropylene sutures (4/0 Prolene; Ethicon, Norderstedt, Germany) were sutured ex vivo into atrial auricles from excised pig hearts. The tissue was treated by bipolar, saline-irrigated RF ablation (Cardioblate; Medtronic, Duesseldorf, Germany), until increase of tissue impedance pointed out a transmural lesion. After fixation in formaldehyde, the sutures were carefully removed and examined for ultrastructural damage using scanning electron microscopy, comparing them to sutures with intentional damage by instrumental grips. Tensile strength was tested applying a force velocity of 200 mm/min. Here, parts from the ablated zones were compared with parts from nonablated zones of the same suture.

RESULTS

We could not find ultrastructural damage in form of heat-induced changes in the helical polypropylene structure. Accordingly, the tensile strength of the ablated sutures (16.5 to 17.5 N) showed no difference to an untreated suture. In contrast, sutures damaged by instruments showed remarkable structural damage and could be torn without force.

CONCLUSION

Bipolar, saline-irrigated RF ablation does not damage polypropylene sutures in spite of the heat applied to the tissue. Therefore, it is safe to create bipolar epi/endocardial lesions of the heart through polypropylene purse-string sutures.

Beneficial effects of intravenously administered N-3 fatty acids for the prevention of atrial fibrillation after coronary artery bypass surgery: a prospective randomized study

BACKGROUND

Atrial fibrillation (AF) is a common complication after coronary artery bypass grafting operation (CABG). Experimental data have shown antiarrhythmic effects of n-3 polyunsaturated fatty acids (PUFA) on myocardial cells. Orally administered PUFA could significantly reduce the rate of postoperative AF. We assessed the efficacy of PUFA for the prevention of AF after CABG. PUFA were given intravenously to prevent variation in bioavailability.

METHODS AND RESULTS

52 patients were randomized to the interventional group, 50 served as controls. In the control group free fatty acids (100 mg soya oil/kg body weight/day) were infused via perfusion pump, starting on admission to hospital and ending at discharge from intensive care. In the interventional group PUFA were given at a dosage of 100 mg fish oil/kg body weight/day. Primary end point was the postoperative development of AF, documented by surface ECG. Secondary end point was the length of stay in the ICU. The demographic, clinical and surgical characteristics of the patients in the two groups were similar. Postoperative AF occurred in 15 patients (30.6 %) in the control and in 9 (17.3 %) in the PUFA group ( P < 0.05). After CABG, the PUFA patients had to be treated in the ICU for a shorter time than the control patients. No adverse effects were observed.

CONCLUSIONS

Perioperative intravenous infusion of PUFA reduces the incidence of AF after CABG and leads to a shorter stay in the ICU and in hospital. Our data suggest that perioperative intravenous infusion of PUFA should be recommended for patients undergoing CABG.

Pulse pressure variation and stroke volume variation during different loading conditions in a paediatric animal model

BACKGROUND

Previous studies in adult patients and animal models have demonstrated that pulse pressure variation (PPV) and stroke volume variation (SVV) can be used to predict the response to fluid administration. Currently, little information is available on the performance of these variables in infants and neonates. The aim of our study was to assess whether PPV and SVV can predict fluid responsiveness in an animal model and to investigate the influence of different tidal volumes applied.

METHODS

PPV and SVV were monitored by pulse contour analysis in 19 anaesthetized and paralysed piglets during ventilation with tidal volumes (V(T)) of 5, 10 and 15 ml/kg both before and after fluid loading with 25 ml/kg of hydroxy-ethyl starch 6% (HES). Cardiac output was measured by pulmonary artery thermodilution and a positive response to HES infusion was defined as >/=20% increase in the stroke volume index (SVI).

RESULTS

Before HES infusion, PPV and SVV were significantly greater during ventilation with a V(T) of 10 and 15 ml/kg than during ventilation with a V(T) of 5 ml/kg (P<0.05). After HES infusion, only ventilation with V(T) 15 ml/kg resulted in a significant increase in PPV and SVV. As assessed by receiver operating characteristic curve analysis, SVV during ventilation with V(T) 10 ml/kg was the best predictor of a positive response to fluid loading (AUC=0.87).

CONCLUSIONS

In this paediatric animal model, we found that SVV during ventilation with 10 ml/kg was a sensitive and specific predictor of the response to fluid loading.

Immediate postoperative extubation after minimally invasive direct coronary artery surgery (MIDCAB)

We were interested whether immediate postoperative extubation and early discharge of the intensive care unit (ICU) is safe in minimally invasive direct coronary artery surgery (MIDCAB) patients. Therefore we retrospectively analyzed the data from 217 patients undergoing MIDCAB from 2/99 to 4/02. Immediate postoperative extubation was possible in 182/217 (83.9%) with eight patients needing reintubation (11.5+/-3.3 h). Ventilation time of the remaining 35 patients was less than 24 h in 31 patients (8.8+/-5.3). Sixty-nine patients (31.8%) were directly transferred from the ICU. Immediate extubation after MIDCAB surgery is safe resulting in an effective use of resources.

Long-term results after surgical correction of atrioventricular septal defects

OBJECTIVE

Review of the results of surgical correction of atrioventricular septal defects (AVSD), identification of risk factors for mortality and failure of left AV valve repair and determination of the impact of cleft closure on postoperative AV valve function.

METHODS

Between 1975 and 1995, 121 consecutive patients (55 males, 66 females) underwent surgery for biventricular correction of AVSD with a median age of 1.2 years and a median weight of 7.6 kg. Sixty-five patients had a complete AVSD, 17 patients an intermediate type, and 39 patients a partial AVSD. The left AV valve (MV) cleft was closed in 53 patients (43.8%). The mean follow-up time is 7.2+/-4.6 years.

RESULTS

Actuarial survival of the whole group after 1 year was 80%, after 10 and 20 years 78 and 65%, respectively. There were 18 early deaths (7-day mortality, 10.7%; 30-day mortality, 14.9%) and eight late deaths. In a univariate analysis, risk factors for early or late death were diagnosis of complete AVSD (P=0.006), no cleft closure (P=0.024), postoperative complications (P<0.0001), age <1.2 years (P=0.017), weight <7.6 kg (P=0.002), PA/Ao pressure ratio >0.7 (P<0.0001), and ECC time >110 min (P=0.002). In the multivariate analysis, postoperative complications (P=0.003) and PA/Ao pressure ratio >0.7 (P=0.001) had parallel effects on the postoperative risk for mortality. Moderate or severe MV regurgitation was present in six patients (6.0%) in the first evaluation after discharge and in 20 patients (20.4%) in the most recent postoperative control. There were 25 reoperations in 17 patients, of which 15 had to be performed for MV regurgitation and two for MV stenosis. Freedom from reoperation was 91% at 1 year, 79% at 10 years, and 76% at 15 and 20 years. We could not identify a statistically significant risk factor for reoperation.

CONCLUSIONS

In patients with AVSD of various morphologies closure of the left AV valve cleft significantly improves outcome without affecting the need for reoperation. Risk factors for early and late death (multivariate analysis) were a pulmonary/aortic pressure ratio >0.7 and the occurrence of any complication after surgery. The concept of an early surgical AVSD correction before an increase in pulmonary vascular resistance and AV valve deformations occur would represent a better surgical option than a late correction as done in our series. Early correction allows for reduction of early mortality, superior long-term survival rates and a high freedom from subsequent valve degeneration.

Tetralogy of Fallot: influence of surgical technique on survival and reoperation rate

BACKGROUND

The influence of different surgical techniques in patients with Tetralogy of Fallot (TOF) on long-term survival and reoperation rate is still a matter of controversy.

PATIENTS AND METHODS

The data of 266 patients (152 male, 114 female, mean body weight: 13.4 +/- 11.9 kg, mean age 4.1 +/- 6.0 years) with TOF, including 30 patients (11.2 %) with TOF/pulmonary atresia, were analyzed retrospectively. A palliative surgical procedure preceded definite correction between 1975 and 1999 in 46 patients (17.5 %). The surgical technique consisted of a transannular patch in 103 patients (40.1 %); in 133 patients (51.8 %), a non-transvalvular technique was used. In 33 patients (12.3 %), a conduit was implanted into the right ventricular outflow tract (RVOT). For surgical access to the cardiac defects, a transventricular approach was used in 138 patients, and a transatrial/trans-pulmonary approach in 26 patients. The mean follow-up time of all patients was 6.6 years.

RESULTS

Kaplan-Meier survival for the entire group was 86.2 % at one year and remained stable at 85.6 % after 5 years. The 30-day mortality was 10.1 % (27 patients). Fatal risk factors were: previous cardiac surgery, preoperative oxygen saturation (SO(2)) < 80 %, diagnosis of pulmonary atresia, prolonged aortic clamping or bypass time, postoperative infections, and early revisions. Freedom from reoperation was 91.6 % after 5, 84.5 % after 10, and 52.6 % after 20 years. There was no correlation between the different surgical techniques (transannular patch, non-transvalvular techniques, transventricular approach) applied and the mortality or the rate of reoperations.

CONCLUSIONS

In our series of TOF patients operated over a period of 25 years, we were unable to assess an influence of the surgical technique used for definite correction on mortality or reoperation rate. Pulmonary atresia in patients with TOF is associated with a higher risk of death and reoperation.

Surgical therapy of a coronary artery fistula draining into the left atrium

Coronary artery fistulas (CAFs) are rare vascular anomalies. We describe a case of CAF draining into the left atrium, combined with an atrial septum defect (ASD) and azygos continuity in a 3-year-old girl. Surgical therapy included closure of the ASD combined with closure of the CAF through a left atrial approach. Even though CAF can be treated by interventional means, surgical correction may be required in the presence of associated cardiac abnormalities.

Correction of tetralogy of Fallot: does the time period of surgery influence the outcome?

BACKGROUND

The perioperative outcome of patients with tetralogy of Fallot (TOF) seems to have improved over the last four decades.

METHODS

To prove this hypothesis, we retrospectively analysed the data of 269 TOF patients operated on between 1975 and 1999 in our institution.

RESULTS

Over the years, younger patients (median age 1975 - 1980: 4.5 years, 1995 - 1999: 0.9 years) were operated on with a lower mortality (1975 - 1980: 8.6 %, 1995 - 1999: 2.4 %). Residual defects such as pulmonary stenosis or insufficiency and VSD occurred with a similar frequency over time, whereas rhythm disturbances were significantly reduced (1981 - 1985: 51.2 %, 1995 - 1999: 24.4 %, p = 0.012). Postoperative length of hospital stay was significantly (p < 0.05) shorter in the years 1995 - 1999 (11.0 - 11.4 days) than in 1975 - 1980 (16.9 +/- 16.5 days).

CONCLUSIONS

Over time periods, there was a trend towards lower mortality and towards operating on patients in a younger age. The rate of rhythm disturbances and the LOS after surgery proved to be reduced during the last decade. These differences did not turn out to be statistically significant. Therefore, we conclude that the time period of surgery has only little impact on the early outcome of patients after definitive correction of TOF.

Two-stage repair of a combined aneurysm of the descending aorta and the aberrant right subclavian artery

In cases of combined aneurysms of the descending aorta and the aberrant right subclavian artery a common surgical strategy has not been clearly elaborated. In this report the case of a 76-year-old male patient with this rare combination of aneurysms is presented. The surgical strategy consisted of a two-stage approach for repairing both aneurysms maintaining the perfusion of the right subclavian and vertebral artery, finally providing an excellent postoperative result even in a patient of this advanced age.

Early angiographic results after revascularization by minimally invasive direct coronary artery bypass (MIDCAB)

OBJECTIVE

Anastomosing the left anterior descending artery (LAD) by use of the internal mammary artery (IMA) via an anterior minithoracotomy represents the most commonly performed minimally invasive direct coronary artery bypass (MIDCAB). However, little is known about angiographic results beyond patency rates.

METHODS

Therefore, a retrospective analysis of 205 consecutive control angiographies was performed evaluating anastomototic patency as well as the angiographic morphology of the left IMA and the LAD.

RESULTS

The overall anastomotic patency rate was 98.0%. As a result of incomplete IMA preparation (6-15 cm) large side branches (n = 4), or an IMA course under tension (n = 6) were occasionally observed. Despite a tension-free course, the IMA appeared fixed to the chest wall without functional compromise in 21 cases. A restrictive thrombus formation occurred once, IMA dissection was not seen. Two of the grafts developed spasms. A distal IMA stenosis >50% was seen in five cases. Stenosis of the anastomosis (>50%) itself was found once, as well as unexpected malinsertation to diagonal branches (n = 4). Compared with preoperative angiograms, de novo stenoses of the LAD were assessed proximal (14< or =50%, 2>50%) and distal (15< or =50%, 2>50%) to the anastomosis. Elevation of the LAD out of the vascular bed was an additional finding (n = 12) in a few cases.

CONCLUSIONS

The overall patency of MIDCAB-LAD-grafting appears to be equivalent to conventional IMA grafting to the LAD. Particular angiographic findings, however, may be directly associated to the applied surgical technique.

Aortic valve replacement: better myocardial protection by cold or warm retrograde blood cardioplegia?

BACKGROUND AND AIMS OF THE STUDY

To determine whether warm blood cardioplegia (BCP) is superior to cold BCP in terms of myocardial protection, we compared warm (37 degrees C) and cold (4 degrees C) continuous retrograde administration of BCP in 40 patients undergoing aortic valve replacement (AVR) in a prospective, randomized study.

MATERIALS AND METHODS

The main subjects of investigation were the myocardial oxygen consumption and the maintenance of the ultrastructure of the tissue. In addition, we looked at intraoperative recordings of time, heart rhythm disturbances, CK/MB serum levels, and inotropic support.

RESULTS

We found, that oxygen consumption is significantly higher during warm BCP (7.95-10.38 ml/min) than during cold BCP (2.11-3.47 ml/min). Mild, reversible myocardial damage occurs during cold and warm BCP. The intraoperative serum potassium level was significantly higher after warm (7.25 mmol/l) than after cold (6.55 mmol/l) BCP. There was no statistically significant difference in the duration of extracorporeal circulation and of cardiac arrest, the CK/MB serum level or the recorded right and left ventricular performance data in the two groups.

CONCLUSIONS

We conclude that continuous retrograde warm BCP is not superior to continuous retrograde cold BCP as far as myocardial protection is concerned. The administration of cold BCP prolongs the tolerated ischemic time of the myocardium and provides a higher safety margin.