[Long-term Outcomes of the Maze Procedure Omitting the Ablation Line to The Superior Vena Cava].

OBJECTIVE: In an effort to avoid postoperative sick sinus syndrome( SSS), we omit the ablation line to the superior vena cava( SVC) in the Cox-mazeⅢ lesion set. We report the long-term outcomes, including the freedom from SSS. METHODS: We studied 102 patients who underwent bi-atrial maze procedure for persistent atrial fibrillation (Af) from 2009 through 2023. Bipolar radio frequency ablation or cryoablation was used except for right-side atriotomy and right atriotomy. Cryoablation was used for atrioventricular annulus. The patient age was 68±9.4. Duration of Af was 3.4±6.5 years (unknown 9 cases). The amplitude of f-wave in V1 was 0.182±0.095 mV and it was<0.1 mV in 19 (18.6%). Diameter of the left atrium was 50±8.9 mm, and left atrial volume index was 89±37 ml/m2. Ninety-one (89.2%) patients underwent concomitant mitral valve surgery. RESULTS: Survival rate was 99% at 1 year and 96% at 5 years. Freedom from Af was 92% at 1 year and 88% at 5 years. Freedom from permanent pacemaker implantation (PPI) was 87% at 1 year and 83% at 5 years. CONCLUSIONS: Defibrillation rate and the incidence of PPI was comparable to those in previous reports after standard Cox-mazeⅢ. SSS after maze for persistent Af seem due to patient.

Internal circular suture annuloplasty for aortic valve repair.

Stabilizing the aorto-ventricular junction is integral in aortic valve repair. We report our technique of internal circular suture annuloplasty. We used a continuous horizontal mattress suture of a single thick expanded polytetrafluoroethylene suture (CV-3). We put 4 stitches per sinus, so the suture was below the cusp attachment line at the nadirs and passed through the interleaflet triangle at the upper aorto-ventricular junction level. The suture was reinforced with pericardial pledgets on both sides of each commissure. We used this technique in 12 patients. The diameter of aorto-ventricular junction was reduced from 25 ± 2 mm to 22 ± 1 mm (n = 11) and was 22 ± 1 mm at the latest follow-up (4-74 months, median 41, n = 10). In 2 patients with large aorto-ventricular junction (27 mm or more), expected annular reduction was not achieved. Our modified technique is simple and seems durable. It may be useful for mild annular dilatation.

Patency of separate tube grafts for intercostal artery reconstruction: Size and length matter.

OBJECTIVES: Low patency is a major concern when using separate tube grafts for intercostal artery reconstruction. Our goal was to elucidate the optimal size and length of grafts from their patency and the computational fluid dynamics (CFD). METHODS: The patency, size and length of separate tube grafts were evaluated in 41 patients. Simulation of CFD was performed in a model derived from a patient with a patent 12-mm graft that was 15 mm long, with 2 simulation models with a smaller (8-mm) or longer (30-mm) graft. RESULTS: A total of 49 grafts were used for intercostal artery reconstruction. There was 1 in-hospital death and 2 spinal cord injuries. The patency rate, which could be evaluated in 46 grafts, was 63% (29/46). It was 71% (24/34) in thoracoabdominal aortic replacement and 42% (5/12) in descending aortic replacement. Among 14 patients in whom all grafts were occluded, no patients developed spinal cord injury. All grafts longer than 25 mm were occluded (n = 5). Eight- and 10-mm grafts showed better patency than 12-mm grafts in thoracoabdominal aortic replacement (P = 0.008) when grafts were shorter than 25 mm. Simulation of CFD revealed vortical flow within the 12-mm graft, which did not reach the intercostal orifice, whereas helical flow was maintained throughout the cardiac cycle within the 8-mm graft. CONCLUSIONS: Eight- and 10-mm grafts seemed better than 12-mm grafts, and grafts should be kept shorter than 25 mm. Simulation of CFD may shed light on the issue of the optimal intercostal artery reconstruction technique.

Surgical Approaches to Single-Stage Extended Aortic Repair from the Ascending to the Distal Descending Aorta.

Single-stage extended replacement from the ascending to the distal descending aorta or beyond is a formidable operation that should be preserved for those who have no other option or those who are physically fit, and should be performed in the experienced centers. Hybrid operations combining open surgical repair with thoracic endovascular aortic repair through a median sternotomy incision are preferable because these operations are less invasive than the extended open aortic repair and the risk of spinal cord ischemia is lower compared with the frozen elephant trunk operation. However, these operations are associated with the inherent demerits of endovascular aneurysm exclusion. When the underlying aortic pathology necessitates extended open aortic repair in a single stage, approaches such as the anterolateral partial sternotomy, straight incision with rib cross, and extended thoracotomy with sternal transection may be useful to provide sufficient exposure for both aortic reconstruction and organ protection, with less surgical stress to the patients.

Brachial plexus injury and upper rib fracture after median sternotomy in cardiac surgery.

OBJECTIVES: Sternal retractors utilized during open-heart surgeries through median sternotomy can cause upper rib fractures which sometimes further leads to brachial plexus injury. We aimed to investigate the incidence of brachial plexus injury and upper rib fractures in open-heart surgeries and how these injuries are associated with each other. METHODS: We investigated 1050 cases during the past five years. The incidence of brachial plexus injury and upper rib fractures after median sternotomy was assessed in all patients and the patients who sustained were evaluated for the affected side, the level of paralysis. RESULTS: Ten cases (0.95%) exhibited brachial plexus injury after median sternotomy. Nine cases developed paralysis on left upper extremity. In all ten cases, sensory and motor nerve impairment were exhibited in the lower plexus. Rib fractures were observed in 35.0% of cases after median sternotomy and the usage of asymmetric sternal retractors to harvest left internal thoracic artery (LITA) significantly affected the side of fracture. CONCLUSION: Sternal retractors utilized during open-heart surgeries through median sternotomy may cause rib fractures and brachial plexus injury, so operators should be aware of these complications.

18-Fluorodeoxyglucose positron emission tomography in the diagnosis of prosthetic aortic graft infection: the difference between open and endovascular repair.

OBJECTIVES: 18-Fluorodeoxyglucose (18F-FDG) positron emission tomography (PET)/computed tomography (CT) has been reported as useful for diagnosing aortic graft infection. However, 18F-FDG uptake may depend upon various factors including open versus endovascular repair and time from surgery. We aimed to elucidate the factors influencing its uptake and the diagnostic value of 18F-FDG PET/CT after open and endovascular repair. METHODS: Hospital database of PET/CT (N = 14 490) and our departmental database were cross-checked to identify those who underwent 18F-FDG PET/CT after aortic repair. Patient's data were retrieved from the chart. Images were reviewed by 2 nuclear medicine specialists in consensus, and the presence of increased 18F-FDG uptake was recorded. The maximum standardized uptake value (SUV max) was measured. RESULTS: Among the 1112 patients who underwent aortic repair between 2011 and 2022, 71 patients were identified. Eighteen patients underwent 18F-FDG PET/CT for suspected graft infection and the remaining 53 patients for other purposes (malignancy, etc.). Fourteen patients were treated as aortic graft infection. They had significantly higher SUV max than those without graft infection [mean 8.64 (standard deviation 2.78) vs 3.40 (standard deviation 0.84); P < 0.01]. In the non-infected grafts, SUV max was higher early after open surgical repair, while it remained low after endovascular repair. CONCLUSIONS: After endovascular aortic repair, a constant cut-off value of 'SUV max = 4.5' seems appropriate for diagnosing graft infection, since it remains low and stable from the early postoperative period. After open surgical repair, it seems acceptable to have 'stepwise cut-off value' depending on the time from surgery.

A Novel Ring Knot Pusher With Closed Triangle Tip for Minimally Invasive Cardiac Surgery.

We created a novel ring-type knot pusher with a closed triangle tip, wherein the thread is never detached from the knot pusher head during the ligation process. This knot pusher has a small head and is suitable for complex fields, such as the subvalvular apparatus of the mitral valve, allowing the surgeons to observe the knot itself. Considering that the thread passes through the inner corner of the triangle during the tying-down process without swinging inside the triangle, this knot pusher allows for a stable and secure ligation.

Radial artery vs saphenous vein grafts for sequential coronary bypass grafting as a second conduit for the left coronary territory.

OBJECTIVE: Although the radial artery graft has an adaptive property to flow demand, its flow characteristics in aorto-coronary sequential bypass grafting are not well elucidated. We evaluated the differences between the vein and radial artery grafts in the patency and the transit time flow meter-derived parameters (flow and pulsatile index), according to the stenosis rate of terminal target vessels and the number of anastomoses, in sequential bypass grafting to the left coronary territories as a second conduit. METHODS: We analyzed 222 patients who underwent isolated on-pump beating coronary artery bypass grafting with an aorto-coronary bypass to the left coronary territory. The patients were divided into radial artery group (n = 154) and vein graft group (n = 68). Sequential bypass was performed 1n 171 patients (127 radial arteries, 44 veins). RESULTS: Flow of the radial artery grafts was lower than that of the vein grafts (40.9 ± 22.3 vs 47.5 ± 23.8 mL/min, p = 0.044), while it became higher as the number of anastomoses per graft increased (1: 28.9 ± 16.3 vs 2: 40.9 ± 19.9 vs 3: 55.8 ± 27.5, p < 0.001). The patency of radial artery grafts was better than that of vein grafts (98.0% vs 92.6%, p = 0.010; p < 0.001 after propensity score weighting). CONCLUSIONS: Although intraoperative flow rate of the radial artery graft is lower, it has sufficient flow reserve for sequential bypass grafting, and its early patency is high enough. Radial artery is suitable for sequential bypass grafting to the left coronary territories as a second arterial conduit.

Simple Height Reduction of the Posterior Leaflet in Robotic Mitral Annuloplasty.

Systolic anterior motion is occasionally encountered during mitral valve repair using neochordal reconstruction for mitral regurgitation owing to large posterior leaflet prolapse. In cases with a redundant posterior leaflet, the risk of systolic anterior motion increases if the redundant posterior leaflet is unresected to decrease the leaflet height. The posterior leaflet was fixed at the anterior annulus, cut near the posterior annulus, and resected into a spindle shape. The excised part of the posterior leaflet was subsequently closed with a continuous suture. Herein, we report our simple height reduction technique of the posterior leaflet, the "curtain technique," performed in robotic surgery.

Functional brain isolation technique for stroke prevention in thoracic endovascular aortic repair.

To prevent embolic stroke during thoracic endovascular aortic repair, we have adopted the brain isolation technique since June 2014 in 9 selected high-risk patients (9/134: 6.7%) having ulcerated or protruding atheromas within the proximal aorta. Cardiopulmonary bypass was used to prevent aortic atheromas from entering the brain. We used a heparin-coated closed-loop cardiopulmonary bypass system incorporating a soft reservoir bag with 1 mg/kg heparin to minimize the disadvantages of extracorporeal circulation. The bypass graft (right axillary-left carotid-left axillary) was used as an arterial inflow in patients undergoing zone-1 landing (n = 8), while peripheral cannulation into 3 brachiocephalic arteries was employed in the remaining patient. Initial pump flow was set at 1.3 l/min/m2, and native cardiac output was reduced by adjusting the reservoir bag volume. Aortography was performed to confirm non-visualization of the arch vessels before catheter manipulation. There was no mortality and 1 solitary left cerebellar infarction.

Clinical feasibility and safety of transoesophageal motor-evoked potential monitoring.

OBJECTIVES: Canine experiments have shown that transoesophageal motor-evoked potential monitoring is feasible, safe and stable, with a quicker response to ischaemia and a better prognostic value than transcranial motor-evoked potentials. We aimed to elucidate whether or not these findings were clinically reproducible. METHODS: A bipolar oesophageal electrode mounted on a large-diameter silicon tube and a train of 5 biphasic wave stimuli were used for transoesophageal stimulation. Results of 18 patients (median age 74.5 years, 13 males) were analysed. RESULTS: There were no mortalities, spinal cord injuries or complications related with transoesophageal stimulation. Transcranial motor-evoked potential could not be monitored up to the end of surgery in 3 patients for unknown reasons, 2 of whom from the beginning. Transoesophageal motor-evoked potential became non-evocable after manipulation of a transoesophageal echo probe in 2 patients. Strenuous movement of the upper limbs during transoesophageal stimulation was observed in 3 patients. In 14 patients who successfully completed both monitoring methods up to the end of surgery (11 thoraco-abdominal and 3 descending aortic repair), the final results were judged as false positives in 6 by transcranial stimulation and in 1 by transoesophageal stimulation. The stimulation intensity was significantly lower and the upper limb amplitude was significantly higher by transoesophageal stimulation, while the lower limb amplitude was comparable. CONCLUSIONS: Transoesophageal motor-evoked potential monitoring is clinically feasible and safe with a low false positive rate. A better electrode design is required to avoid its migration by transoesophageal echo manipulation. Further studies may be warranted. CLINICAL REGISTRATION NUMBER: UMIN000022320.

Bipolar transesophageal thoracic spinal cord stimulation: A novel clinically relevant method for motor-evoked potentials.

OBJECTIVE: Although transesophageal motor-evoked potential elicited by monopolar cervical cord stimulation is more stable and rapid in response to ischemia than transcranial motor-evoked potential in canine experiments, direct cervical alpha motor neuron stimulation precludes clinical application. We evaluated a novel stimulation method using a bipolar esophageal electrode to enable thoracic cord stimulation. METHODS: Twenty dogs were anesthetized. For bipolar transesophageal stimulation, the interelectric pole distance was set at 4 cm. Changes in amplitude in response to incremental stimulation intensity (100-600 V) were measured to evaluate stability. Spinal cord ischemia was induced by aortic balloon occlusion at the T8 to T10 level for 10 minutes to evaluate response time or at the T3 to T5 level for 25 minutes to evaluate prognostic value. Neurological function was evaluated using the Tarlov score at 24 and 48 hours postoperatively. RESULTS: Bipolar transesophageal stimulation was successful in all animals and their forelimb waveforms were identical to those after transcranial stimulation. The minimum stimulation intensity to produce >90% of the maximum amplitude was significantly lower in both monopolar and bipolar transesophageal stimulation than in transcranial stimulation (n = 5). Time to disappearance and recovery (>75%) of the hindlimb potentials were significantly shorter by both monopolar and bipolar transesophageal stimulation than by transcranial stimulation (n = 5). Correlation with neurological outcomes was comparable among all stimulation methods (n = 10). CONCLUSIONS: Motor-evoked potential can be elicited by bipolar transesophageal thoracic cord stimulation without direct cervical alpha motor neuron stimulation, and its stability and response time are comparable to those elicited by monopolar stimulation.

Morphological modification of the aortic annulus in tricuspid and bicuspid valves after aortic valve reimplantation: an electrocardiography-gated computed tomography study†.

OBJECTIVES: Aortic valve-sparing operations have been shown to produce fewer valve-related complications than valve replacement. The aortic root is a morphological and functional unit in which the annulus plays an important role on dynamism, shape and geometry of the valve with different results in bicuspid aortic valves (BAVs) or tricuspid aortic valves (TAVs). The aim is to evaluate the differences in the size and shape of the aortic annulus between native BAVs and TAVs using ECG-gated computed tomography (CT) after a reimplantation procedure. METHODS: We selected 35 patients scheduled for aortic valve reimplantation who underwent good-quality preoperative and postoperative ECG-gated contrast-enhanced CT scan of the aortic root. Twenty-three patients had TAV, 8 patients type 1 BAV and 4 patients type 0 BAV. Major diameter and minor diameter, perimeter (P) and area (A) were measured. The shape of the aortic annulus was considered 'circular' or 'elliptic' according to the Ellipticity Index. We also selected a subgroup of 18 patients (9 TAVs and 9 BAVs) to evaluate annular shape and size variations through the cardiac cycle and to study the expansibility both in the preoperative and in the postoperative phases. RESULTS: Preoperative CT scans showed an elliptic shape of TAVs (Ellipticity Index 1.3 ± 0.1), a circular shape of type 0 BAVs (1.1 ± 0.1) and an intermediate behaviour of type 1 BAVs, suggesting a possible gradual spectrum of circularity from TAVs to type 1 BAVs to type 0 BAVs. Postoperative CT scans did not show any significant difference in annular shape among the 3 groups, which demonstated a similar roundness, obviating the preoperative differences. Analysing the expansibility of the aortic annulus during the cardiac cycle, we observed that it was completely absent in the preoperative phase in BAVs, while in the postoperative phase, both TAVs and BAVs showed a small but similar expansibility after the annular reduction. CONCLUSIONS: There is a possible gradual spectrum in terms of shape, from native TAVs, to type 1 BAVS to type 0 BAVs. These differences are eliminated in the postoperative phase, suggesting an active role of the annuloplasty on the geometry of the aortic annulus. The preoperative analysis showed a complete inelasticity of BAVs, which was partly restored in the postoperative phase.

Japanese perspective in surgery for thoracoabdominal aortic aneurysms.

OBJECTIVE: Operative mortality and morbidity after thoracoabdominal aortic surgery remain high. We report our strategy and outcomes, especially those of spinal cord protection. METHODS: Outcomes of 178 patients (age: 26-88 years) who underwent thoracoabdominal aortic replacement were retrospectively analyzed. 65 had aortic dissection, 14 had infected aneurysms, and 22 presented with rupture. Operations were non-elective in 24 and redo through re-thoracotomy in 21. Extent of replacement was Crawford-I in 39, II in 26, III in 78, and IV in 35. Staged repair was recently preferred, which resulted in decrease in extent II repair and increase in redo since 2009. Operations were performed under distal aortic perfusion and multi-segmental sequential repair to maximize collateral blood flow, and deep hypothermic circulatory arrest was preserved for those requiring open aortic anastomosis (n = 20). A total of 166 separate grafts were used for intercostal reconstruction in 88 patients, which was guided by preoperative feeding artery localization. Their patency was studied by postoperative MD-CT in 74 patients for 145 grafts. RESULTS: There were 3.9% hospital mortality and 5.1% spinal cord injury. Preoperative feeding artery localization resulted in reduced number of reconstruction and improved patency, and grafts connecting to the feeding artery were patent in 92%. Results of redo operations were not different (no mortality and spinal cord injury) from the de novo operations. CONCLUSIONS: Our concept of spinal cord protection, which was based on selective intercostal reconstruction while maximizing spinal cord collateral blood flow, seems justified.

Carotid stenosis with impaired brain flow reserve is associated with an increased risk of stroke in on-pump cardiovascular surgery.

OBJECTIVES: To prevent haemodynamic stroke during cardiovascular surgery in patients with carotid stenosis, we routinely evaluated magnetic resonance angiography and selectively evaluated brain perfusion single-photon emission computed tomography with acetazolamide challenge. Off-pump surgery was preferred when cerebral blood flow reserve was impaired. This strategy's usefulness was investigated. METHODS: Among the 1059 consecutive patients who underwent preoperative carotid screening by magnetic resonance angiography, 84 (7.9%) patients had >50% stenosis; 45 of them underwent brain single-photon emission computed tomography. The severity of cerebral blood flow compromise was estimated by the proportion of Stage 2 area in the affected territory, in which both resting blood flow (<32 ml/min) and flow reserve (<10%) were reduced. RESULTS: Perioperative stroke occurred in 1.7% overall (18/1059), in 6% (5/84) of those with carotid stenosis and in 1.3% (13/975) of those without stenosis (P = 0.010). On subgroup analysis, carotid stenosis was associated with an increased risk of stroke in the on-pump surgery group [n = 949, 5/59 (9%) with stenosis vs 11/890 (1.1%) without stenosis, P = 0.002], while it was not in the off-pump group [n = 110, 0/25 (0%) with stenosis vs 2/85 (2%) without stenosis, P = 0.59]. With respect to the role of acetazolamide single-photon emission computed tomography, 2 of the 4 patients with Stage 2 area >10% undergoing on-pump surgery without preceding carotid revascularization developed stroke, while none of the 21 patients with Stage 2 area <10% undergoing on-pump surgery developed stroke (P = 0.020). CONCLUSIONS: Carotid stenosis is a risk factor for perioperative stroke in on-pump surgery. Patients with large Stage 2 area (>10%) are at increased risk of perioperative stroke when on-pump surgery is performed.

Endovascular Treatment of a Ruptured Innominate Artery Aneurysm in Behcet Disease.

In Behcet disease (BD), vascular complication such as false aneurysm formation is common after surgical treatment in the arterial lesion, and the optimal treatment method remains controversial. Concerning the innominate artery aneurysm, lack of experience due to its rarity in vasculo BD makes decision making even more difficult. We report a ruptured innominate artery aneurysm in a 70-year-old man with BD, which was successfully treated by innominate artery stent grafting through the right common carotid artery, axillo-axillary artery bypass grafting, and right subclavian artery coil embolization. The patient is doing well without any vascular complications at eighth postoperative month.

Transesophageal versus transcranial motor evoked potentials to monitor spinal cord ischemia.

OBJECTIVES: We have previously reported that transesophageal motor evoked potential is feasible and more stable than transcranial motor evoked potential. This study aimed to investigate the efficacy of transesophageal motor evoked potential to monitor spinal cord ischemia. METHODS: Transesophageal and transcranial motor evoked potentials were recorded in 13 anesthetized dogs at the bilateral forelimbs, anal sphincters, and hindlimbs. Spinal cord ischemia was induced by aortic balloon occlusion at the 8th to 10th thoracic vertebra level. In the 12 animals with motor evoked potential disappearance, occlusion was maintained for 10 minutes (n = 6) or 40 minutes (n = 6) after motor evoked potential disappearance. Neurologic function was evaluated by Tarlov score at 24 and 48 hours postoperatively. RESULTS: Time to disappearance of bilateral motor evoked potentials was quicker in transesophageal motor evoked potentials than in transcranial motor evoked potentials at anal sphincters (6.9 ± 3.1 minutes vs 8.3 ± 3.4 minutes, P = .02) and hindlimbs (5.7 ± 1.9 minutes vs 7.1 ± 2.7 minutes, P = .008). Hindlimb function was normal in all dogs in the 10-minute occlusion group, and motor evoked potentials recovery (>75% on both sides) after reperfusion was quicker in transesophageal motor evoked potentials than transcranial motor evoked potentials at hindlimbs (14.8 ± 5.6 minutes vs 24.7 ± 8.2 minutes, P = .001). At anal sphincters, transesophageal motor evoked potentials always reappeared (>25%), but transcranial motor evoked potentials did not in 3 of 6 dogs. In the 40-minute occlusion group, hindlimb motor evoked potentials did not reappear in 4 dogs with paraplegia. Among the 2 remaining dogs, 1 with paraparesis (Tarlov 3) showed delayed recovery (>75%) of hindlimb motor evoked potentials without reappearance of anal sphincter motor evoked potentials. In another dog with spastic paraplegia, transesophageal motor evoked potentials from the hindlimbs remained less than 20%, whereas transcranial motor evoked potentials showed recovery (>75%). CONCLUSIONS: Transesophageal motor evoked potentials may be superior to transcranial motor evoked potentials in terms of quicker response to spinal cord ischemia and better prognostic value.