Transapical aortic cannulation in the operation of acute type A aortic dissection

From June 2003 to November 2006, transapical aortic cannulation was performed in 73 patients (41 men and 32 women, mean age 63 years, 64 hemiarch repair and 9 total arch replacement) with acute type A aortic dissection. A 1-cm incision was made in the apex of the left ventricle, and a 7-mm soft and flexible cannula was passed through the apex and across the aortic valve until positioned in the ascending aorta under guidance by transesophageal echocardiography. In all cases, cardiopulmonary bypass flow was sufficient. There were no malperfusion events. Our results showed that transapical aortic cannulation was secure and useful for repair of acute type A aortic dissection.     

Transaortic inflow and outflow cannula for centrifugal mechanical assistance

A specific cannula allowing single site transaortic inflow and outflow cannulation for centrifugal assist devices is described. The cannula is inserted through a straight 18 mm collagen coated Dacron tube anastomosed to the anterior aspect of the ascending aorta. The inflow conduit of the cannula is positioned into the left ventricle through the aortic valve, and the end hole of the outflow conduit is positioned in the ascending aorta. The cannula was evaluated in vivo in 3 adult pigs by the institution of a centrifugal pump for left ventricular support. Optimal flow varied between 5 and 6 L/min and mean aortic pressure between 55 and 70 mm Hg throughout the 3 days of left ventricular support. Recently, we employed this cannula in a patient who was not able to be weaned from cardiopulmonary bypass for the institution of left ventricular support using a centrifugal pump. The cannula provided effective inflow and outflow drainage with an optimal flow of 5.2 L/min throughout the 72 h of support. The patient was successfully weaned from support on the fourth postoperative day. This rational transaortic approach of cannulation using this specific cannula is a refined implantation technique which allows direct left ventricular inflow drainage, reduces the time of implantation, spares left ventricular myocardium, avoids bleeding that is sometimes encountered at other cannulation sites, and avoids compression of the heart by cannulas.     

Apical aortic cannulation: application of an old method with new paraphernalia

An instrument assembly consisting of a special aortic cross-clamp and double-lumen perfusion cannula is presented. The application of these instruments allows occlusion of the ascending aorta traversed by the perfusion cannula inserted directly or through the apex of the heart as well as simultaneous left ventricular venting.     

Transapical aortic cannulation via left lateral thoracotomy for descending thoracic and thoracoabdominal aortic surgery

Two patients underwent surgery for a chronic type B dissection using a total cardiopulmonary bypass (CPB) with transapical arterial cannulation. At surgery, a total CPB was established by cannulating the left femoral artery and the ascending aorta via the ventricular apex. The patients were cooled to 30°C. The proximal anastomosis was done after cross-clamping the aortic arch between the left carotid artery and the left subclavian artery in both cases. In the first case, the entire descending thoracic aorta was replaced, and two pairs of intercostal arteries were reconstructed. The other patient underwent replacement of the proximal descending thoracic aorta. Neither patient experienced any complications. Transapical aortic cannulation is a useful option during descending thoracic and thoracoabdominal aortic surgery. It can provide more stable circulation during the cross-clamping, more gentle manipulation of the aorta by nonpulsatile flow, and more liberty in temperature control.     

Proximal aortic perfusion with passive cerebral flow: a method to prevent cerebral embolism in the arch and descending aortic operation

Antegrade aortic perfusion is preferable in arch and descending aortic operations. We describe a left lateral approach using an ascending aortic cannula, temporarily relocated within the distal aorta to maintain hypothermic cardiopulmonary bypass of the lower torso. This modification provides continual antegrade systemic perfusion and passive retrograde cerebral flow during arch repair. It minimizes the risk of embolization into the brachiocephalic arteries of debris and malperfusion of the dissected aorta.     

Occlusion of a calcified ascending aorta with a Foley catheter in aortocoronary bypass--case report

Heavily calcified ascending aorta predisposes to aortic injury and distal embolization during total or partial cross-clamping, during the performance of open-heart procedures. Placement of the arterial cannula may be particularly difficult, occasionally virtually impossible using the standard technique, while placing the clamp on such aorta may be extremely risky. We present a case where we have used a Foley-balloon catheter to occlude the densely calcified ascending aorta, during a aorta-coronary bypass procedure, thus completely avoiding the use of the total aortic clamp.     

Flow analysis of ventricular assist device inflow and outflow cannula positioning using a naturally shaped ventricle and aortic branch

Tip geometry and placement of rotary blood pump inflow and outflow cannulae influence the dynamics of flow within the ventricle and aortic branch. Cannulation, therefore, directly influences the potential for thrombus formation and end-organ perfusion during ventricular assist device (VAD) support or cardiopulmonary bypass (CPB). The purpose of this study was to investigate the effect of various inflow/outflow cannula tip geometries and positions on ventricular and greater vessel flow patterns to evaluate ventricular washout and impact on cerebral perfusion. Transparent models of a dilated cardiomyopathic ventricle and an aortic branch were reconstructed from magnetic resonance imaging data to allow flow measurements using particle image velocimetry (PIV). The contractile function of the failing ventricle was reproduced pneumatically, and supported with a rotary pump. Flow patterns were visualized around VAD inflow cannulae, with various tip geometries placed in three positions in the ventricle. The outflow cannula was placed in the subclavian artery and at several positions in the aorta. Flow patterns were measured using PIV and used to validate an aortic flow computational fluid dynamic study. The PIV technique indicated that locating the inflow tip in the left ventricular outflow tract improved complete ventricular washout while the tip geometry had a smaller influence. However, side holes in the inflow cannula improved washout in all cases. The PIV results confirmed that the positioning and orientation of the outflow cannula in the aortic branch had a high impact on the flow pattern in the vessels, with a negative blood flow in the right carotid artery observed in some cases. Cannula placement within the ventricle had a high influence on chamber washout. The positioning of the outflow cannula directly influences the flow through the greater vessels, and may be responsible for the occasional reduction in cerebral perfusion seen in clinical CPB.     

Transapical approach in transcatheter cardiovascular interventions

The left ventricular apex has excellent accessibility to the aortic valve, mitral valve, left ventricular outflow tract and thoracic aorta. Although the number of transapical approach in transcatheter aortic valve replacement has been decreasing in recent years, it is still a useful option for patients with very poor peripheral vascular access. The apex has been chosen as a primary access site for many devices of transcatheter mitral valve repair/replacement and mitral valve-in-valve procedures. Additionally, the transapical approach has been used for other transcatheter cardiovascular interventions such as paravalvular leak repair after mitral or aortic valve replacement, pseudoaneurysm repair of the left ventricular outflow tract, and thoracic endovascular aortic repair. Herein, I review our own experience and articles of the transapical transcatheter cardiovascular interventions and discuss about clinical usability, technical tips and complications of the transapical approach in various transcatheter cardiovascular interventions.     

Hypothermic circulatory arrest through a left thoracotomy in a 12-year-old child with aortic coarctation

Surgical correction of adult complex aortic coarctation using hypothermic circulatory arrest often requires central cannulation to secure cerebral perfusion. It is not easy to place the cannula in the ascending aorta, however, especially in children undergoing surgery through a left thoracotomy. In a 12-year-old male with hypoplastic distal aortic arch, we placed an arterial cannula in the ascending aorta using the Seldinger puncture technique through the stenotic segment of the distal aortic arch. Replacement of the stenotic segment with a 20 mm-size Dacron graft was then routine. The ascending aorta was exposed only for the proximal anastomosis. The left subclavian artery was also reconstructed. This central cannulation technique is simple and is useful in repairing complex aortic coarctation.     

Prominent Septal Hypertrophy: A Contra‐Indication for Transapical Aortic Valve Implantation?

We report a case of transapical aortic valve implantation in a patient with severe left ventricular hypertrophy. The valve was deployed but failed to attain stable seating because of a hypertrophied septal ridge encroaching on the landing zone. Moderate perivalvar insufficiency was also noted. A second valve was deployed in an attempt to achieve stable seating and correct the perivalvar leak. This was unsuccessful and the two-valve complex embolized into the ascending aorta. The valves were moved and seated in the proximal descending thoracic aorta. The technical issues of transapical aortic valve implantation in patients with severe left ventricular hypertrophy are reviewed.     

Transapical aortic cannulation using a deep hypothermic procedure through a left thoracotomy for acute traumatic aortic rupture

We describe a transapical aortic cannulation procedure through a left thoracotomy for a case of acute traumatic aortic rupture. A 26-year-old man was involved in a motor vehicle accident and admitted in a state of hypovolemic shock. Chest computed tomography findings revealed a rupture of the proximal portion of the descending aorta and a massive hematoma around the aorta extending into the thoracic cavity. Under hypothermic circulatory arrest, he underwent an emergency graft replacement through a left thoracotomy. We used transapical aortic cannulation together with femoral cannulation, in order to avoid malperfusion of the brain and upper body that can occur as a result of retrograde perfusion. The postoperative outcome was favorable. Transapical cannulation is a useful alternative for hypothermic aortic operations through a left thoracotomy.     

Differential perfusion: a new technique for isolated brain cooling during cardiopulmonary bypass

BACKGROUND: The purpose of this study was to determine the feasibility of differential perfusion of the aortic arch and descending aorta during cardiopulmonary bypass using a cannula designed for aortic segmentation. METHODS: Pigs weighing 57 kg (n = 8), underwent cardiopulmonary bypass using the dual lumen aortic cannula. An inflatable balloon separated proximal (aortic arch) and distal (descending aorta) ports. During differential perfusion, the aorta was segmented and the arch and descending aorta perfused differentially using parallel heat exchangers. Ability to independently control brain and body temperature, cardiopulmonary bypass flow rate and mean arterial blood pressure was determined. RESULTS: During differential perfusion cerebral hypothermia (27 degrees C) with systemic normothermia (38 degrees C) was established in 23 minutes. Independent control of arch and descending aortic flow and mean arterial blood pressure was possible. Analysis of internal jugular venous O2 saturation data indicated an increase in the ratio of cerebral O2 supply to demand during differential perfusion. CONCLUSIONS: A cannulation system segmenting the aorta allows independent control of cerebral and systemic perfusion. This device could provide significant cerebral protection while maintaining the advantages of warm systemic cardiopulmonary bypass temperatures.     

Isolated myocardial perfusion during arch repair

Repair of coarctation of the aorta with severe hypoplasia of the aortic arch or interrupted aortic arch was performed in 5 patients using a modification of the usual technique that consisted of isolated myocardial perfusion during arch repair. The aortic cross-clamp was placed on the ascending aorta distal to the aortic cannula. Cardiopulmonary bypass flow was reduced to about 10% of full flow, achieving a line pressure of 35 to 45 mm Hg to keep the heart perfused and beating during arch repair. Once the aortic arch was repaired, total body perfusion was continued as usual and intracardiac repair was performed. Isolated myocardial perfusion for aortic arch reconstruction reduces myocardial ischemic time.     

Left Atrial-Aortic/Femoral Bypass with a Centrifugal Pump without Systemic Heparin during Surgery on the Descending Aorta

Abstract: Active or passive bypass to support the distal circulation during cross-clamping of the descending thoracic aorta has been reported to decrease the incidence of paraparesis, to reduce left ventricle afterload, and to preserve distal organ perfusion. The aim of this study was to describe and to evaluate a perfusion technique for surgery on the descending aorta in humans. Nine patients underwent surgery on the descending thoracic aorta. The left atrium was cannulated using a Carmeda bioactive surface cannula. Distal cannulation sites were the left common femoral artery or the aorta below the involved segment. The cannulae were connected to a BioMedicus centrifugal pump via Carmeda bioactive surface tubings and pump heads. No systemic heparin was used. Cross-clamp time was 51 ± 6 min, and the pump flow was 2.3 ± 0.2 L/min. The mean arterial pressure in the upper body was 81 ± 4 mm Hg and 68 ± 5 mm Hg in the lower. Seven patients were discharged from hospital. Two patients with aortic rupture died; one died on the operating table, and the other, neurologically intact, died 4 days postop-eratively due to multiorgan failure. No patients suffered spinal cord injury. It is concluded that active bypass without systemic heparin during cross-clamping of the descending aorta is simple and safe.     

Easy aortic cannulation: a transxyphoid approach

An easy aortic cannulation technique in minimally invasive pediatric cardiac surgery is described. We have developed a dilator which fits an aortic perfusion cannula. The aortic cannula over the dilator with a hole for passage of a guide wire is inserted into the ascending aorta by the Seldinger technique. Using this technique, the cannula never slips off, even at a slant angle to the aorta owing to the guidance of the guide wire. We recommend this safe and reliable technique for insertion of an aortic cannula into the ascending aorta in minimally invasive pediatric cardiac surgery.     

Interaction of a Transapical Miniaturized Ventricular Assist Device With the Left Ventricle: Hemodynamic Evaluation and Visualization in an Isolated Heart Setup

New left ventricular assist devices (LVADs) offer both important advantages and potential hazards. VAD development requires better and expeditious ways to identify these advantages and hazards. We validated in an isolated working heart the hemodynamic performance of an intraventricular LVAD and investigated how its outflow cannula interacted with the aortic valve. Hearts from six pigs were explanted and connected to an isolated working heart setup. A miniaturized LVAD was implanted within the left ventricle (tMVAD, HeartWare Inc., Miami Lakes, FL, USA). In four experiments blood was used to investigate hemodynamics under various loading conditions. In two experiments crystalloid perfusate was used, allowing visualization of the outflow cannula within the aortic valve. In all hearts the transapical miniaturized ventricular assist device (tMVAD) implantation was successful. In the blood experiments hemodynamics similar to those observed clinically were achieved. Pump speeds ranged from 9 to 22 krpm with a maximum of 7.6 L/min against a pressure difference between ventricle and aorta of ～50 mm Hg. With crystalloid perfusate, central positioning of the outflow cannula in the aortic root was observed during full and partial support. With decreasing aortic pressures the cannula tended to drift toward the aortic root wall. The tMVAD could unload the ventricle similarly to LVADs under conventional cannulation. Aortic pressure influenced central positioning of the outflow cannula in the aortic root. The isolated heart is a simple, accessible evaluation platform unaffected by complex reactions within a whole, living animal. This platform allowed detection and visualization of potential hazards.     

Ascending aorta cannulation in acute type A aortic dissection

Objective: Antegrade perfusion for type A acute aortic dissection prevents malperfusion and retrograde cerebral embolism during cardiopulmonary bypass. Prompt establishment of antegrade perfusion via ascending aorta may improve the surgical results of type A dissections, especially in the situations of hemodynamic instability. Thus, we evaluated the efficacy of use of the dissected ascending aorta as an alternative arterial inflow. Methods: Between 2002 and 2006, 32 patients underwent prosthetic graft replacement of the ascending aorta or hemiarch for acute type A aortic dissection. The ascending aorta was routinely cannulated, in addition to the femoral artery, with a heparin-coating flexible cannula for arterial inflow, using Seldinger technique, and by epiaortic ultrasonographic guidance (n = 6). Antegrade systemic perfusion via ascending aorta was performed. Results: Ascending aorta cannulation was safely performed in all cases. There was no malperfusion or thromboembolism due to ascending aorta cannulation. Cardiopulmonary bypass was established within 30 min after skin incision. There was one in-hospital death due to duodenal bleeding (1/32 = 3.1%), two cases of cerebral infarction (2/32 = 6.3%), and one case of pulmonary embolism. Twenty-nine patients (29/32 = 90.6%) were discharged in New York Heart Association class I and have been followed up uneventfully for a mean of 17 months. Conclusions: Antegrade perfusion via the ascending aorta was successfully performed with low mortality and morbidity. With ultrasound-guided Seldinger technique, ascending aorta cannulation has a potential to be a simple and safe option that enables rapid establishment of antegrade systemic perfusion in patients with acute type A aortic dissection.     

Surgery for thoracic aortic aneurysms involving the distal arch through a left thoracotomy

Surgical outcome for thoracic aortic aneurysms involving the distal arch via a left thoracotomy using retrograde cerebral perfusion combined with profound hypothermic circulatory arrest was reviewed. Twelve patients with a atherosclerotic aortic aneurysm between 1994 and 1997 were involved. A proximal aortic anastomosis was made by means of an open aortic technique. For the first four patients, oxygenated arterial blood from cardiopulmonary bypass was perfused retrogradely through a venous cannula positioned into the right atrium. In the last eight cases, venous blood provided by a low-flow perfusion of the lower half body via the femoral artery, which was still oxygen-saturated, was circulated passively in the brain in a retrograde fashion with the descending aorta clamped. Prosthetic replacement was done between the distal arch and the proximal descending aorta in 6 patients and from the distal arch to the entire descending thoracic aorta in 6 patients. The median duration of hypothermic circulatory arrest and continuous retrograde cerebral perfusion was 36 minutes and 33 minutes respectively. The overall outcome was satisfactory without early mortality--all patients survived, although an octogenarian died of respiratory failure 1 year postoperatively. Another octogenarian with a ruptured aneurysm developed delay of meaningful consciousness, and other two patients with a severely atherosclerotic aneurysm suffered permanent neurological dysfunction (stroke) presumably due to an embolic episode. The safe and simple combination of profound hypothermic circulatory arrest, retrograde cerebral perfusion, and open aortic anastomosis protects the brain adequately and produces satisfactory results in surgery for aortic aneurysms involving the distal arch through a left thoracotomy.     

Modified aortic cannulation for cardiopulmonary bypass in neonatal piglet model

Abstract   Animal models are still essential for studying effects of cardiopulmonary bypass. We describe modifications in cannulation technique for a neonatal piglet model, which may also serve as an "everyday" technique in congenital cardiac surgery (age of animals <7 days; mean body weight 2.9 ± 0.5 kg). Surgical approach through median sternotomy and cardiopulmonary bypass was established by cannulating right atrium and ascending aorta with a modified aortic root cannula. Left ventricular venting was performed placing a cannula into the apex and connecting this to the venous drainage line. The described technique has been applied in 19 cases, all but one were without technical problems.     

Aortic arch reconstruction using regional perfusion without circulatory arrest.

OBJECTIVES: Deep hypothermic circulatory arrest during repair of aortic arch anomalies may induce neurological complications or myocardial injury. Regional cerebral and myocardial perfusion may eliminate those potential side effects. METHODS: From March 2000 to March 2002, 48 neonates or infants with complex arch anomaly were operated on using the regional perfusion technique. Thirty-three patients were male and the median age was 24 days (range 5-301 days). Preoperative diagnosis consisted of coarctation or interruption of the aorta associated with ventricular septal defect (group I, n = 26) and arch anomaly with complex intracardiac defects such as hypoplastic left heart syndrome or its variants (group II, n = 22). Arterial cannula was inserted through the innominate artery and the flow rate was regulated to about 50-100 ml/kg per min during regional perfusion. Simultaneous myocardial perfusion was maintained using a Y-connected infusion line. Cardioplegia was applied during intracardiac repair. RESULTS: Cardiopulmonary bypass and aortic cross-clamp times were 154 +/- 49 and 39 +/- 34 min, respectively. Temporary circulatory arrest for intracardiac procedures was performed in eight patients. However, the mean arrest time was minimized (range 1-18 min). The descending aorta clamping time was 33 +/- 16 min. Operative mortality rates in each group were 0 and 18.2% (0/26 and 4/22). Late mortality rates were 0 and 11.1% (0/26 and 2/18) during 9.1 months of follow-up. Complications consisted of low cardiac output in eight cases, transient neurological problems in two cases, and transient renal insufficiency in two cases, respectively. CONCLUSIONS: Regional perfusion is feasible and can be used with acceptable results. It may reduce potential complications following aortic arch reconstruction using circulatory arrest. However, repair of aortic arch in the patients with complex intracardiac defects still imposes a significant rate of mortality and morbidity.