Francesco Matteucci

Assessment of a continuous blood gas monitoring system in animals during circulatory stress

BackgroundThe study was aimed to determine the measurement accuracy of The CDI™ blood parameter monitoring system 500 (Terumo Cardiovascular Systems Corporation, Ann Arbor MI) in the real-time continuous measurement of arterial blood gases under different cardiocirculatory stress conditionsMethodsInotropic stimulation (Dobutamine 2.5 and 5 μg/kg/min), vasoconstriction (Arginine-vasopressin 4, 8 and 16 IU/h), hemorrhage (-10%, -20%, -35%, and -50% of the theoretical volemia), and volume resuscitation were induced in ten swine (57.4 ± 10.7 Kg).Intermittent blood gas assessments were carried out using a routine gas analyzer at any experimental phase and compared with values obtained at the same time settings during continuous monitoring with CDI™ 500 system. The Bland-Altman analysis was employed.ResultsBias and precision for pO2 were - 0.06 kPa and 0.22 kPa, respectively (r2 = 0.96); pCO2 - 0.02 kPa and 0.15 kPa, respectively; pH -0.001 and 0.01 units, respectively ( r2 = 0.96). The analysis showed very good agreement for SO2 (bias 0.04,precision 0.33, r2 = 0.95), Base excess (bias 0.04,precision 0.28, r2 = 0.98), HCO3 (bias 0.05,precision 0.62, r2 = 0.92),hemoglobin (bias 0.02,precision 0.23, r2 = 0.96) and K+ (bias 0.02, precision 0.27, r2 = 0.93). The sensor was reliable throughout the experiment during hemodynamic variations.ConclusionsContinuous blood gas analysis with the CDI™ 500 system was reliable and it might represent a new useful tool to accurately and timely monitor gas exchange in critically ill patients. Nonetheless, our findings need to be confirmed by larger studies to prove its reliability in the clinical setting.

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.

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.

Impact of renal function impairment assessed by CKDEPI estimated glomerular filtration rate on early and late outcomes after coronary artery bypass grafting

BACKGROUND We explore the association between short- and long- term adverse outcomes following coronary artery bypass grafting (CABG) and the degree of preoperative renal dysfunction classified on glomerular fraction estimated with Chronic Kidney Disease-Epidemiology Collaboration equation (eGFRCKD-EPI). We also try to identify cut-off values of eGFRCKD-EPI able to predict post-CABG unfavorable events and assess whether a reclassification with new thresholds is necessary. METHODS One-thousand-one-hundred-eighty-six consecutive patients undergoing CABG between 2005 and 2014 were categorized in 4 groups according to the eGFRCKD-EPI: Group 1 (≥60ml/min/1.73m2; n=1199), Group 2 (45-59ml/min/1.73m2; n=358), Group 3 (30-44ml/min/1.73m2; n=171) and Group 4 (≤29ml/min/1.73m2; n=126). Median follow-up was 66months [IQR 46-84]. RESULTS eGFRCKD-EPI ≤30ml/min/1.73m2, ≤41ml/min/1.73m2, ≤27ml/min/1.73m2 and ≤29ml/min/1.73m2 were strong predictors of early mortality (OR 5.88 [95% CI 2.59-11.25]), stroke (2.59 [1.43-3.71]), prolonged length of stay (3.49 [1.24-5.92]) and postoperative dialysis (3.68 [1.34-4.91]), respectively. In addition, eGFRCKD-EPI ≤26ml/min/1.73m2, ≤25ml/min/1.73m2, ≤35ml/min/1.73m2 and ≤29ml/min/1.73m2 predicted all-cause death (hazard ratio 2.74 [95% CI 2.10-3.92] cardiovascular death (sub-hazard ratio 2.11 [95% CI 1.42-3.90]), myocardial infarction (2.01 [1.32-3.70]) and heart failure (2.24 [1.41-3.93]), respectively. Analyses corrected by age and left ventricular ejection fraction confirmed these findings. CONCLUSIONS In our experience, the use of the eGFRCKD-EPI equation led to categorization with a significantly lower number of patients at risk for post-CABG complications. This might have important clinical repercussions on allocation of healthcare resources and more targeted prevention and management of CABG complications.