Takuya Nomoto

Monitoring of regional cerebral oxygenation by near-infrared spectroscopy during continuous retrograde cerebral perfusion for aortic arch surgery

OBJECTIVEnTo assess the value of monitoring of regional cerebral oxygen saturation (rSO2) during aortic arch surgery using continuous retrograde cerebral perfusion (CRCP) in conjunction with profound hypothermic circulatory arrest (HCA).nnnMETHODSnThe rSO2 of 12 consecutive patients was monitored non-invasively using near-infrared spectroscopy (NIRS) and the data were analyzed statistically.nnnRESULTSnThe mean duration of HCA with CRCP was 62-/+14.1 min. The mean CRCP flow rate was 226+/-163 ml/min. Surgical outcomes were favorable with only a single hospital death (8.3%). However, the rSO2 decreased gradually in all patients during HCA, even combined with CRCP, and fell to 46+/-8.7% on average. It did not change so greatly before HCA and returned finally to its initial level at the end of re-warming. Only one patient developed a permanent neurologic deficit; this patient showed the greatest decrease of rSO2 from 56% to 29% after the longest HCA of 88 min. Two parameters, End-rSO2 (the ratio of post- to pre-HCA rSO2) and delta-rSO2 (the rate of decrease from preto post-HCA rSO2) were obtained since the initial values of rSO2 before surgery differed. There were linear correlations between the CRCP flow rate and each of these two parameters. A multiple regression analysis also revealed a linear equation relating the parameters, which allowed prediction of the safe duration of HCA in different conditions of CRCP and a more favorable adjustment of the CRCP condition in each patient.nnnCONCLUSIONSnThe study suggests that the combination of HCA and CRCP has a limit of safe duration in spite of its potential usefulness for brain protection, and that rSO2 monitored by NIRS is useful in testing for adequate brain protection. It is hoped that monitoring of rSO2 can facilitate prediction of the safe duration of HCA with CRCP and a more favorable adjustment of CRCP.

Aortic arch repairs through three different approaches.

OBJECTIVESnThe outcome of aortic arch repairs by means of three different approaches between 1990 and January 2000 was reviewed.nnnMETHODSnIn total 39 patients aged 71.5+/-6.2 years were operated on. The three different surgical approaches depended on the anatomical positions of the aneurysms and on their proximal or distal extension; a median approach was employed in 23 patients, whereas a left postero-lateral approach was used in eight patients. More recently, in eight cases a left antero-lateral approach was applied. All patients underwent open aortic anastomosis without any clamp on or around the aortic arch. During the procedure, the brain was protected by a combination of profound hypothermic circulatory arrest and several techniques of retrograde cerebral perfusion.nnnRESULTSnPermanent cerebral dysfunction occurred in four patients: two in the median approach and two in the left postero-lateral approach. There were two hospital deaths (5.3%) and six late deaths, all of which belonged either to the median group or to the postero-lateral group. The antero-lateral approach did not produce any cerebral dysfunction, early death, or late death.nnnCONCLUSIONSnThe outcome of aortic arch repairs using profound hypothermic circulatory arrest and variable techniques of retrograde cerebral perfusion, by means of three different approaches, was satisfactory. Of the three approaches, the antero-lateral approach can be employed easily, whether aneurysms extend proximally or distally.

β-blocker therapy in patients after aortic valve replacement for aortic regurgitation

BACKGROUNDnbeta-blocker therapy for dilated or ischemic cardiomyopathy is now an accepted and effective treatment. However, little is known about its efficacy in patients with postoperative impaired left ventricular function. This retrospective study was designed to assess the effects of beta-blocker therapy in patients after aortic valve replacement (AVR) for aortic regurgitation (AR).nnnMETHODSnA total of 59 patients who underwent AVR for chronic AR were assigned to four groups. Twelve patients were treated with both ACE inhibitors and beta-blockers, 12 patients with only ACE inhibitors, eight patients with only beta-blockers, and 27 patients without beta-blockers or ACE inhibitors. A postoperative echocardiographic study was performed one year after surgery.nnnRESULTSnThe heart rate was significantly reduced in patients with beta-blockers despite the use of ACE inhibitors after surgery. Postoperative left ventricular volume was more significantly decreased in beta patients than in non-beta patients despite the use of ACE inhibitors. There were also significant reductions in left ventricular mass index in ACE+beta patients compared to ACE+non-beta patients. However, there were no significant differences in NYHA functional class and survival rate between beta patients and non-beta patients.nnnCONCLUSIONSnbeta-blocker therapy may improve cardiac performance by reducing cardiac volume and mass in patients with impaired LV function after AVR for AR.

Two-Stage Repair for Aortic Regurgitation With Interrupted Aortic Arch

We performed two-stage repair for a rare adult case of interrupted aortic arch with aortic regurgitation and sinus of Valsalva aneurysm. A lateroisthmic bypass was established with minimal thoracotomy and partial clamping of the descending aorta to preserve collateral circulation. This was followed by aortic root reconstruction with a prosthetic graft and valve for aortic regurgitation with sinus of Valsalva aneurysm. This less invasive two-stage repair for such a rare pathology may facilitate smooth recovery of the patient.

Warm heart operation in a patient with myotonic dystrophy

Myotonic dystrophy is the most severe form of myotonic disorder. Hypothermia or hyperkalemia may cause generalized muscle contraction during heart operations. We successfully repaired an atrial septal defect and pulmonary stenosis in a patient with myotonic dystrophy using systemic normothermia with continuous normokalemic coronary perfusion. This is the second reported case of a patient with myotonic dystrophy who underwent a cardiac operation.

Mitral Valve Repair in a Patient With Severe Porcelain Aorta

We repaired the mitral valve in a patient with severe porcelain aorta. Significant mitral regurgitation developed in a 66-year-old woman with heavy calcification throughout the whole aorta. At operation, cardiopulmonary bypass was properly established by combined axillary and femoral arterial cannulations for sufficient systemic flow. Likewise, the combination of a superior mitral approach and profound hypothermic fibrillatory arrest in conjunction with low-flow cardiopulmonary bypass allowed us to repair the mitral valve successfully.

Early and mid-term outcomes of cardiac and thoracic aortic surgery in over-75-year-olds with postoperative quality of life assessment

The early and mid-term outcomes of cardiac and thoracic aortic surgery were reviewed in seventy-two consecutive patients aged 75 years and older, together with assessment of postoperative quality of life. Twenty-six patients had ischemic heart disease, twenty had valvular heart disease, one had congenital heart disease, and twenty-five had thoracic aortic aneurysm. Twenty-five (34.7%) required an emergency operation. There were 6 early deaths (8.3%) and 11 late deaths (17.2%), of which the emergency cases had higher mortality of 5 early deaths (20.0%) and 3 late deaths (15.0%). In particular, most cases with a ruptured thoracic aortic aneurysm died eventually from various complications including neurological dysfunction. The others with a non-ruptured aneurysm also had atherosclerotic aortic or arterial lesions which caused a lethal cerebrovascular accident or ischemic heart disease. The quality of life of 51 of 53 survivors was assessed using the Rosser and Watts index being based on disability and distress scores. The response was satisfactory--the disability score was 2.6 +/- 1.9 and the distress score was 1.4 +/- 0.4. The patients with a thoracic aortic aneurysm had worse quality of life scores than those of the ischemic heart disease or valvular heart disease patient-groups because of various perioperative complications. Our experiences demonstrate that the results including the postoperative quality of life following cardiac and aortic surgery in the elderly is satisfactory except for emergency cases. The results would prompt us to operate, if possible, electively in their stable conditions, even on elderly over-75-year-olds.

A case of type A dissection involving right aortic arch

Aortic dissection involving right aortic arch (RAA) is quite rare. A patient with RAA and aberrant left subclavian artery (type 3 RAA) developed type A dissection, but successfully underwent ascending and hemiarch replacement under hypothermic circulatory arrest with continuous retrograde cerebral perfusion. We approached the lesion through a midline sternotomy and could reconstruct the first two arch vessels involved by the dissection. We would have added bilateral thoracotomy, if the distal arch vessels had required reconstruction. To our knowledge, this is the first report of successful surgical repair for type A dissection involving RAA.

Two different techniques of retrograde cerebral perfusion for thoracic aortic surgery through a left thoracotomy.

The authors used profound hypothermic circulatory arrest and continuous retrograde cerebral perfusion for aortic surgery that involved the distal arch through a left thoracotomy. For the first seven patients, oxygenated blood from cardiopulmonary bypass was perfused retrogradely through a venous cannula positioned into the right atrium. In the last 11 cases, venous blood, provided by a perfusion from the lower body, was circulated passively in the brain with the descending aorta clamped. The period of profound hypothermic circulatory arrest was 34.6 +/- 11.1 min, and continuous retrograde cerebral perfusion was 31.3 +/- 11.1 min. Seventeen patients survived, but there was one early death. Two patients with a severely atherosclerotic aneurysm developed permanent neurological dysfunction. The combination of profound hypothermic circulatory arrest, continuous retrograde cerebral perfusion and open aortic anastomosis through a left thoracotomy protects the brain adequately, and facilitates evacuation of debris and air in the aortic arch. It produces satisfactory results for aortic surgery that involves the distal arch.

A case of pryce type I intrapulmonary sequestration

A twenty-year-old asymptomatic man hospitalized because of a vascular murmur and abnormal shadow in the left lower lung on X-ray film. An aortogram revealed an abnormal artery arising from the descending thoracic aorta and supplying the left basal segment, which had no other pulmonary arteries. Although lung ventilation scintigraphy demonstrated reduced ventilation to the left lower lobe, bronchogram showed an almost normal bronchial tree except that peripheral branches were slightly thin. A clinical diagnosis of Pryce type I intrapulmonary sequestration was made, and left lower lobectomy was performed successfully. We have analyzed 31 cases of Pryce type I intrapulmonary sequestration in Japan. A vascular murmur is often heard, and a chest X-ray usually shows either a mass shadow or increased vascular markings. In most of those cases, an abnormal artery arises from the descending thoracic aorta and it supplies the left basal segment. Because this type of sequestration causes hemoptysis and infections, surgical intervention is indicated.