Pieter Lozekoot

Modalities and Effects of Left Ventricle Unloading on Extracorporeal Life support: a Review of the Current Literature

Veno‐arterial extracorporeal membrane oxygenation (V‐A ECMO) support is increasingly used in refractory cardiogenic shock and cardiac arrest, but is characterized by a rise in afterload of the left ventricle (LV) which may ultimately either further impair or delay cardiac contractility improvement. The aim of this study was to provide a comprehensive overview regarding the different LV venting techniques and results currently available in the literature.

Is ganglionated plexi ablation during Maze IV procedure beneficial for postoperative long-term stable sinus rhythm?☆

BACKGROUND We investigated the role of surgical ablation targeting the autonomous nervous system during a Cox-Maze IV procedure in the maintenance of sinus rhythm at long-term follow-up. METHODS The patient population consisted of 519 subjects with persistent or long-standing persistent atrial fibrillation (AF) undergoing radiofrequency Maze IV during open heart surgery between January 2006 and July 2013 at three institutions without (Group 1) or with (Group 2) ganglionated plexi (GP) ablation. Recurrence of atrial fibrillation off-antiarrhythmic drugs was the primary outcome. Predictors of AF recurrence were evaluated by means of competing risk regression. Median follow-up was 36.7 months. RESULTS The percentage of patients in normal sinus rhythm (NSR) off-antiarrhythmic drugs did not differ between groups (Group 1-75.5%, Group 2-67.8%, p = 0.08). Duration of AF ≥ 38 months (p = 0.01), left atrial diameter ≥ 54 mm (0.001), left atrial area ≥ 33 cm(2) (p = 0.005), absence of connecting lesions (p= 0.04), and absence of right atrial ablation (p < 0.001) were independently associated with high incidence of AF recurrence. In contrast the absence of GP ablation was not a significant factor (p = 0.12). CONCLUSIONS GP ablation did not prove to be beneficial for postoperative stable NSR. A complete left atrial lesion set and biatrial ablation are advisable for improving rhythm outcomes. Randomized controlled trials are necessary to confirm our findings.

Short intra-aortic balloon pump in a swine model of myocardial ischaemia: a proof-of-concept study

OBJECTIVES This proof-of-concept study examined the haemodynamic performance as well as the coronary and visceral organ perfusion using a new short balloon for intra-aortic counterpulsation (IABP) in a swine model of myocardial ischaemia. METHODS Eighteen healthy pigs underwent 120-min ligation of the left anterior descending coronary artery followed by 6 h of reperfusion, and they were randomly assigned into 3 groups undergoing IABP implantation with a 35-ml short balloon (n = 6), a 40-ml short balloon (n = 6) or no IABP implantation (controls, n = 6). Haemodynamics, and visceral and coronary flows were measured at baseline (t0), at 2 h of ischaemia (t1) and every hour thereafter until 6 h of reperfusion (from tR1 to tR6), respectively. RESULTS Mesenteric and renal flows increased significantly at tR1 only in the IABP groups (all, P < 0.001) and were significantly higher than controls throughout the reperfusion periods (P < 0.001). Coronary systolic and diastolic blood flows increased only at tR1 in the IABP groups (all, P < 0.001) but were higher than controls at tR1-tR6. The IABP was associated with enhanced haemodynamics compared with controls. No difference was detected using different balloon volumes (all, P > 0.05). CONCLUSIONS The new short balloon significantly increased visceral flow, enhanced haemodynamics and improved coronary circulation during reperfusion following myocardial ischaemia in our experimental model.

The Optimal Weaning Strategy for Intraaortic Balloon Counterpulsation: Volume-Based Versus Rate-Based Approach in an Animal Model

BACKGROUND Changes in hemodynamics, coronary circulation, visceral flow, and biochemical marker rate reduction or volume deflation for intraaortic balloon pump discontinuation were assessed. METHODS Twelve healthy pigs were randomly assigned to two groups, the rate-based (RB, n = 6) and volume-based weaning groups (VB, n = 6). Hemodynamics and visceral and coronary flows were measured at baseline after 2 hours of intraaortic balloon pump 1:1, during the first 5 hours of weaning (frequency rate reduced to 1:2 in the RB group and volume decreased by 10%/h in the VB group), after 1 hour of frequency rate 1:3 in the RB group or a volume decrease by 75% in the VB group, 2 hours after withdrawal, and 4 hours after withdrawal. RESULTS The animals weaned by progressive VB deflation showed a greater degree of vasodilation, better cardiac output and stroke volume, fewer negative values of cardiac cycle efficiency, and higher dP/dTmax compared with those weaned by RB reduction (p < 0.05 for all). The VB group also exhibited increased coronary flow, lower oxygen consumption of the myocardium, and coronary resistance during VB weaning (p < 0.05 for all). The serum lactate level was lower in the VB group at each experimental point (p < 0.05 for all), but visceral flows were scarcely affected by the weaning method. CONCLUSIONS Volume reduction was the most effective weaning method considering that frequency reduction weaning was responsible for significant negative effects on hemodynamics and coronary circulation.

Vascular complications following intra-aortic balloon pump implantation: an updated review.

Background: The use of the intra-aortic balloon pump (IABP) as a support device remains controversial due to the fact that a number of studies have shown no benefit in end mortality whilst using this device. One of the reasons for this could be the increase in vascular complications when using the pump. Therefore, the aim of the present review was to assess the current literature available with regards to IABP vascular complications during the clinical situation. Methods: A literature search was performed, searching for IABP complications in adult human studies between 1990 and 2016. Results: A total of 20 reports were identified as fitting the criteria of this study. The majority of vascular complications were limb ischemia, bleeding or mesenteric ischemia. The overall incidence of vascular complications ranged from 0.94% to 31.1%. Diabetes, peripheral vascular disease and hypertension, as well as smoking were all identified as risk factors for complications following IABP. Furthermore, studies supported the use of sheathless balloon insertion to reduce the risk of complications. Conclusion: Major vascular complications, including limb and mesenteric ischemia as well as bleeding and hemorrhage, have been associated with IABP. However, the incidence of these complications was generally low. Further studies are still required to truly understand the risk/benefit associated with the use of IABP.

Comparing short versus standard-length balloon for intra-aortic counterpulsation: results from a porcine model of myocardial ischaemia–reperfusion

OBJECTIVES We compare a short and a standard-size balloon with same filling volumes to verify the differences in terms of visceral flow, coronary circulation and haemodynamic performance during aortic counterpulsation in an animal model of myocardial ischaemia-reperfusion injury. METHODS Eighteen healthy pigs underwent 120-min ligation of the left anterior descending coronary artery followed by 6 h of reperfusion, and they were randomly assigned to have intra-aortic balloon counterpulsation (IABP) with a 40-ml short-balloon (n = 6) or a 40-ml standard-length balloon (n = 6), or to undergo no IABP implantation (controls, n = 6). Haemodynamics and visceral and coronary flows were measured at baseline (t0), at 2 h of ischaemia (t1) and every hour thereafter until 6 h of reperfusion (from tR1 to tR6), respectively. RESULTS Mesenteric flows increased significantly at tR1 only in the short-balloon group (P < 0.001) and it was constantly higher than in the standard-balloon group regardless of mean arterial pressure, systemic vascular resistance and cardiac output (CO; all, P < 0.001). Renal blood flows were significantly increased during IABP treatment with values constantly and significantly higher in short balloons at any following experimental step (all, P < 0.05). IABP improved CO and coronary blood flow, and reduced afterload, myocardial resistances and myocardial oxygen consumption without differences between the short and the standard-length balloon (all, P > 0.05). CONCLUSIONS The short balloon prevents visceral ischaemia and, compared with the standard-size balloon, it does not lose IABP beneficial cardiac and coronary-related effects. Further studies are warranted to confirm our findings.

Is visceral flow during intra-aortic balloon pumping size or volume dependent?

Aim: We evaluated the influence of intra-aortic balloon size and volume on mesenteric and renal flows. Methods: Thirty healthy swine underwent 120-minute ligation of the left anterior descending coronary artery followed by 6 hours of reperfusion. Then, they were randomly assigned to the following five groups of animals, with six animals in each group: no intra-aortic balloon pump (IABP), a short 35-mL IABP, a short 40-mL IABP, a long 35-mL IABP and a long 40-mL IABP. Superior mesenteric artery (SMA) and renal flows were measured at baseline (t0), at 2-hour ischemia (t1) and every hour thereafter until 6 hours of reperfusion (from tR1 to tR6). Results: SMA flows increased significantly at tR1 only in the two short IABP groups (p<0.001) and balloon volume did not appear to affect flows which, at any experimental time-point, were comparable using 35 mL or 40 mL balloons (p>0.05). Renal flows appeared to be influenced by balloon length, but not by volume. Indeed, flows in the renal arteries rose during IABP treatment; the increase was significantly higher in the short balloon groups and throughout the whole reperfusion (all, p<0.001). Conclusions: Changes in visceral perfusion during IABP assistance were significantly related to balloon length, but not to its volume. This could be relevant for the evolution of balloon engineering design in order to reduce the incidence of mesenteric ischemia following IABP. Further research is necessary to confirm these findings.

Guideline adherence in antithrombotic treatment after concomitant ablation surgery in atrial fibrillation patients

OBJECTIVES We investigated real-life oral anticoagulation (OAC) treatment after surgical ablation and examined its adherence to current recommendations. We also explored factors related to OAC use preoperatively and at follow-up. METHODS One hundred and fifteen patients with atrial fibrillation (AF) were evaluated during 12-month follow-up after surgery. Patients were divided into two categories according to the congestive heart failure, hypertension, age ≥75 years, diabetes and prior stroke [or transient ischaemic attack or thromboembolism] (CHADS2) score: 60 patients were assigned to the high-risk group (CHADS2 score ≥2) and 55 to the low-risk group (CHADS2 score ≤1). OAC use was defined as guideline adherent, undertreatment or overtreatment. RESULTS Baseline overall guideline adherence was 62%. OAC was underprescribed in high-risk patients and overprescribed in low-risk patients (both, P < 0.001). The only factor associated with OAC use after logistic regression analysis were age >75 years (P = 0.01) and preoperative AF > paroxysmal (P = 0.013). Overall guideline adherence at 12-month follow-up showed a trend towards a better adherence in the sinus rhythm (SR) subgroup (74% vs 55%, P = 0.02). OAC was underprescribed in high-risk patients and overprescribed in low-risk patients (both P < 0.001). After logistic regression analysis, preoperative OAC use (P = 0.007) and other indications for OAC (P = 0.01) were predictors of anticoagulation treatment. CONCLUSIONS Real-life OAC prescription in AF patients showed a moderate guideline adherence, with high-risk patients being undertreated and low-risk patients being overtreated. These findings stress the importance that antithrombotic treatment in patients undergoing AF surgery needs to be critically re-evaluated.