Quantitative evaluation of flow patterns in perfusion cannulae by a new magnetic resonance imaging method

Mitral valve surgery: current status and future prospects of the minimally invasive approach

Introduction: During the past five years the approach to procedural planning, operative techniques and perfusion strategies for minimally invasive mitral valve surgery (MIMVS) has evolved. With the goal to provide a maximum of patient safety the procedure has been modified according to individual patient characteristics and is largely based on preoperative imaging.Areas covered: In this review article we describe the important factors in image based therapy planning and simulation, different access strategies, the operative key-steps, a rationale use of devices, and highlight a few future developments in the field of MIMVS. Published studies were identified through pearl growing, citation chasing, a search of PubMed using the systematic review methods filter, and the authors' topic knowledge.Expert opinion: With the help of expert teams including surgeons specialized in mitral repair, anesthesiologists and perfusionists a broad spectrum of mitral valve pathologies and related pathologies can be treated with excellent functional outcomes. Avoiding procedure related complications is the key for success for any MIMVS program.

Red-Colored Urine in the Cardiac Surgical Patient-Diagnosis, Causes, and Management

Red-colored urine occurring in the intraoperative and early postoperative periods after cardiac surgery is often a cause for concern. This observation may be a result of hematuria from pathology within the urinary tract, anticoagulant-related nephropathy, drug-induced acute interstitial nephropathy, excretion of heme pigment-containing proteins, such as myoglobin and hemoglobin, and hemolysis occurring during extracorporeal circulation. Within the kidneys, heme-containing compounds result in pigment nephropathy, which is a significant contributory factor to cardiac surgery-associated acute kidney injury. Concerted efforts to reduce red blood cell damage during cardiopulmonary bypass, together with early recognition of the at-risk patient and the institution of prompt therapeutic intervention, may improve outcomes. This review addresses the diagnosis, causes, and management of red-discolored urine occurring during and after cardiac surgery.

In vivo comparison of the optiflow and EZ glide aortic dispersion cannulas

OBJECTIVES

Morbidity associated with coronary artery bypass grafts and embolization during aortic cannulation is strongly related to patient characteristics/comorbidities, arterial cannulation site used and the shape of arterial cannulae tips. The desired features of an arterial cannula should be to mitigate the morbid effects of these cannulas and to focus on achieving higher blood flows with lower cannula pressures (CPs).

MATERIALS AND METHODS

To evaluate the in vivo performance of two aortic dispersion flow cannulas: the Optiflow (Sorin Group, Italy) and EZ Glide (Edwards Lifesciences). They were evaluated for CPs, pump-flow rates (FRs), and plasma-free hemoglobin (Hb) over a 12-month period. Data were collected in a prospective, randomized (1:1), nonblinded, monocentric study with a cohort of 30 patients (optiflow group N = 15; EZ Glide group N = 15).

RESULTS

The optiflow cannula was found to have decreasing CPs as the pump FRs were increased (112.3 ± 10.9 vs 131.1 ± 11.4 mm Hg; P < .001). Results indicated no significant differences between groups for increases in plasma free Hb (P = .41) and total microembolic signals counts during the period of cardiac surgery (P = .63).

CONCLUSIONS

Both optiflow and EZ Glide dispersion flow arterial cannulas performed well, but the optiflow cannula demonstrated an ability to increase pump FRs with lower arterial line and CPs than the EZ Glide cannula. This implies an ability to improve peripheral perfusion while reducing cannula shear stress and the risk of endothelial damage, thereby having the potential to reduce the risk of atherosclerotic plaque dislodgement.

Quantitative haemodynamic evaluation of aortic cannulas

We have designed a new type of aortic cannula for extracorporeal circulation which we hypothesize has superior haemodynamic characteristics compared with existing types. The aim of the study was to perform a quantitative evaluation of the haemodynamic performance of commercially available aortic cannulas against our new design. Six existing cannulas and two self-designed, modified DLP cannulas were investigated. Pressure drop, peak velocity and wall thickness were obtained from in vitro experiments. Pressure drop and turbulent stresses were obtained by in vivo experiments. At 5 L/min the pressure drops of the new design were 18 - 25 mmHg in vitro and 20 mmHg in vivo compared with 25 - 92 mmHg in vitro and 28 - 90 mmHg in vivo for the six commercially available cannulas. Turbulent stresses of the new design varied between 25 and 50 N/m2 in vivo compared with 125 - 500N/m2. Both in vivo and in vitro results showed a clear haemodynamic superiority of the new cannula-tip design compared with all existing types.