Open and closed chest extrathoracic cannulation for cardiopulmonary bypass and extracorporeal life support: methods, indications, and outcomes

Routine preoperative doppler ultrasound examination of arterial system in patients undergoing cardiac surgery is beneficial: A retrospective study

Background:

Presence of peripheral vascular disease enhances surgical risk in cardiac surgical patients. Prior knowledge of peripheral arterial disease may help the physician make changes in the monitoring and cardiopulmonary bypass cannulation plans. It is claimed that the incidence of peripheral vascular disease in cardiac surgical patients ranges from 11 to 30%.

Aims:

This study was conducted to understand the characteristics of peripheral vascular disease and their implication on cardiac surgery.

Settings and Design:

This was a prospective study undertaken in a tertiary referral hospital.

Materials and Methods:

All adult patients who underwent cardiac surgery during the period of six months were included. A Doppler examination of the neck, upper limb, abdomen and lower limb was carried out by our inhouse radiologist. The incidence of peripheral vascular disease, the implication on invasive pressure monitoring site and cannulation for cardiopulmonary bypass or intraaortic balloon pump or extracorporeal membrane oxygenation were made note of.

Results:

During the said period, six hundred twenty eight patients underwent cardiac surgery, of whom five hundred and sixty-one patients who underwent CABG surgery. All these were subjected to Doppler examination. We observed peripheral arterial disease in 105 patients (20%). In general men suffered from PAD more often than women. Monitoring site of invasive arterial pressure, the choice of beating heart surgery, insertion of intraaortic balloon pump, femoral arterial route for cardiopulmonary bypass were some of the decision that were altered.

Conclusions:

Performing Doppler examination in cardiac surgical patients may yield important data that might prevent complications and support patient safety.

The Effect of Additional Stepwise Venous Inflow on Differential Hypoxia of Veno-Arterial Extracorporeal Membrane Oxygenation

Use of femoral-femoral veno-arterial (VA) extracorporeal membrane oxygenation (ECMO) for cardiopulmonary support during lung transplantation can be inadequate for efficient distribution of oxygenated blood into the coronary circulation. We hypothesized that creating a left-to-right shunt flow using veno-arterio-venous (VAV) ECMO would alleviate the differential hypoxia. Total 10 patients undergoing lung transplantation were enrolled in this study. An additional inflow cannula was inserted into the right internal jugular (RIJ) vein for VAV ECMO. During left one-lung ventilation using a 1.0 inspired oxygen fraction (FiO₂), the left-to-right shunt flow was incrementally increased from 0 to 500, 1,000, and 1,500 ml/min. The arterial oxygen partial pressure (PaO₂) and oxygen saturation (SaO₂) were measured at the proximal ascending aorta and right radial artery. The ascending aorta gas analysis revealed that six patients had a PaO₂/FiO₂ ratio less than 200 mm Hg at a 0 ml/min shunt flow. The PaO₂ (SaO₂) values were 48.5 ± 14.8 mm Hg (80.9 ± 11.6%) at the ascending aorta and 77.8 ± 69.7 mm Hg (83.3 ± 13.2%) at the right radial artery. As the left-to-right shunt flow rate increased over 1,000 ml/min, the PaO₂ and SaO₂ values for the ascending aorta and right radial artery significantly increased. In conclusion, femoral-femoral VA ECMO can produce suboptimal coronary oxygenation in patients unable to tolerate one-lung ventilation. A left-to-right shunt using VAV ECMO can alleviate the differential hypoxia.

Effect of Prior Sternotomy on Outcomes in Transvenous Lead Extraction

Background:

A history of open-heart surgery has been a heavily debated topic in transvenous lead extraction. This study evaluates the impact of prior sternotomy on transvenous lead extraction outcomes.

Methods:

Data for all patients undergoing transvenous lead extraction at a tertiary referral center were prospectively gathered from 2004 to 2017. Relevant clinical information was compared between patients with a history of sternotomy before transvenous lead extraction and those without. After considering baseline differences, multivariate regression, and propensity-matched analysis were performed. Outcome variables included major and minor complication rates, clinical success, and in-hospital mortality as defined by the 2017 Heart Rhythm Society consensus statement.

Results:

Of 1480 patients in the study period, 455 had a prior sternotomy. When compared with patients with no prior sternotomy, those with prior sternotomy were more likely to be older, male, and present with more comorbidities and leads targeted for extraction. No statistical differences were identified in major and minor complication rates ( P =0.75, P =0.41), clinical success rate ( P =0.26), and in-hospital mortality ( P =0.08). In patients with prior sternotomy, there were no instances of pericardial effusion after extraction. Prior sternotomy was not an independent predictor of clinical or procedural outcomes. No associations were elucidated after propensity-matched analysis.

Conclusions:

In a large, single-center series, no differences in clinical or procedural outcomes were elucidated between patients with a history of sternotomy and those without. Patients with sternotomies before lead extraction who experienced vascular or cardiac perforations clinically presented with hemothoraces rather than pericardial effusions.

Performance Increase in Venous Drainage for Mini-Invasive Heart Surgery: Superiority of Self-Expanding Cannulas

Objective

Originally, the Smartcanula principle (collapsed insertion and expansion in situ) was developed for venous drainage by gravity. However, in minimally invasive surgery, augmentation with either constrained force vortex pumps or vacuum is often used. The current study was set up to assess whether smaller diameters of self-expanding venous cannulas are sufficient in conjunction with venous drainage augmentation resulting in smaller access orifices.

Methods

To evaluate cannulas intended for cardiopulmonary bypass, an in vitro circuit was set up with silicone tubing between the test cannula encased in a lower reservoir, the centrifugal pump, and after an upper reservoir. Afterload was set arbitrarily at 60 mm Hg using a centrifugal pump. The pressure value was measured using Millar pressure transducers. Flow rate (Q) was measured using an ultrasonic flow meter calibrated with volume tank and timer. Revolutions per minute of the centrifugal pump were calibrated with a stroboscope. Data display and data recording were controlled using a Lab View application. Self-expanding (24F Smartcanula) and control (25F Biomedicus) cannulas were used.

Results

Sixty measurements were recorded. At pump speed of 1500, 1570, 2000, 2500, and 3000 rpm, the Q values were 3.6, 5.2, 6.6, 9.3, and 11.8 L/min for the 24F self-expanding cannula and 3, 4.3, 5.4, 7.5, and 9.3 L/min for the control cannula. The pressure values were 3.6, −5.4, −15.9, −45.3, and 80.6 mm Hg. Biomedicus 25F showed Q values from 16% to 19% less as compared with 24F Smartcanula. The pressure values were 6, 7, 4, 2, and 2 times more as compared with 24F Smartcanula.

Conclusions

Our experimental evaluation demonstrated the superior performance of the Smartcanula with its self-expanding design in comparison with the reference commercially available standard cannulas. The Smartcanula with its small diameter is particularly welcome for minimally invasive surgery.

Left Brachiocephalic Vein Cannulation in Bicaval Venous Drainage Is Safe, Effective, and Technically Advantageous

Direct cannulation of both venae cavae (bicaval venous cannulation) is the gold standard for right atrial isolation in intracavitary surgery, but there has been no consensus about an alternative site. Therefore, we studied an alternative method for bicaval venous drainage in which the left brachiocephalic vein (LBCV) is cannulated instead of the superior vena cava. From 2012 through 2014, we performed routine LBCV cannulation in 150 consecutive patients as part of bicaval venous drainage before right atrial isolation. We prospectively collected demographic information, operative data, total pump and LBCV cannula flows with their respective calculated and indexed rates, central venous pressures, and perioperative complications. All patients survived surgery. There were no adverse technical outcomes or functional deficits associated with the technique. The mean indexed LBCV cannula flow was 1,520 ± 216 mL/min/m(2), representing an LBCV cannula-to-calculated pump-flow ratio of 64%. The mean central venous pressure during right atrial isolation was 3.7 ± 1.9 mmHg. Cannulation of the LBCV is intrinsically a safe and reproducible procedure with proven hemodynamic adequacy. Its versatility can be an asset to surgical techniques and perfusion methods. Furthermore, the hemodynamic results in our series promise alternative intrathoracic and extracardiac cannulation sites for mini-extracorporeal circulation, on-pump beating-heart procedures, and short-term circulatory assist device implementation.

Hybrid configurations via percutaneous access for extracorporeal membrane oxygenation: a single-center experience

Use of extracorporeal membrane oxygenation (ECMO) in adults has surged in recent years. Typical configurations are venovenous (VV), which provides respiratory support, or venoarterial (VA), which provides both respiratory and circulatory support. In patients supported with VV ECMO who develop hemodynamic compromise, an arterial limb can be added (venovenous-arterial ECMO) to provide additional circulatory support. For patients on VA ECMO who develop concomitant respiratory failure in the setting of some residual cardiac function, an oxygenated reinfusion limb can be added to the internal jugular vein (venoarterial-venous ECMO) to improve oxygen delivery to the cerebral and coronary circulation. Such hybrid configurations can provide differential support for various forms of cardiopulmonary failure. We describe 21 patients who ultimately received a hybrid configuration at our institution between 2012 and 2013. Eight patients (38.1%) died during ECMO support, four patients (19.0%) died after decannulation but before hospital discharge, and nine patients (42.9%) survived to hospital discharge. Our modest survival rate is likely related to the complexity and severity of illness of these patients, and this relative success suggests that hybrid configurations can be effective. It serves patients well to maintain a flexible and adaptable approach to ECMO configurations for their variable cardiopulmonary needs.

ECMO cannulation controversies and complications

Advances in extracorporeal life support have expanded indications for use extending beyond patients undergoing cardiac surgery. The approach to cannulation in patients requiring extracorporeal membrane oxygenation should be individualized and based on the specific clinical scenario in which the need arises. Adherence to proper techniques of vessel visualization, exposure, and cannulation along with accurate placement of cannulae will optimize flows and minimize complications in this setting. Patients in need of mechanical circulatory support require input from a multidisciplinary team approach with systematic clinical evaluation to optimize outcome. If hemodynamics do not initially permit the successful separation from mechanical support, then a systematic search for potentially reversible patient and/ or pump related factors should be undertaken. The success of this therapy is predicated on patient selection, a multidisciplinary team approach in the intensive care unit, adherence to precise technical principles, and repeated patient evaluation.

Mycotic Pseudoaneurysm of the Ascending Aorta at Site of Aortic Cannulation

Reoperation for pseudoaneurysm of the ascending aorta presents a surgical challenge. Instituting femorofemoral bypass and establishing hypothermic circulatory arrest is a well-known strategy, although not free from complications. We report a case of mycotic pseudoaneurysm after coronary artery bypass in a 53-year-old man, at the site of previous aortic cannulation, and review the surgical strategies proposed to manage this pathologic entity.