Twelve-Month Patency With the PAS-Port Proximal Connector Device: A Single Center Prospective Randomized Trial

Clinical outcomes of automated anastomotic devices: A metanalysis

Background and Aims

We investigated neurological events, graft patency, major adverse cardiovascular events (MACEs), and mortality at 1 year following coronary artery bypass grafting (CABG) surgery using automated proximal anastomotic devices (APADs) and compared the overall rates with the current literature.

Methods

A systematic review of all available reports of APADs use in the literature was conducted. Cumulative incidence and 95% confidence interval (CI) were the main statistical indexes. Nine observational studies encompassing a total of 718 patients were included at the end of the selection process.

Results

The cumulative event rate of neurological complications was 4.8% (lower‐upper limits: 2.8‐8.0, P < .001; I² = 72.907%, P = .002; Egger's test: intercept = –2.47, P = 0.16; Begg and Mazumdar test: τ = −0.20, p = 0.57). Graft patency was 90.5% (80.4 to 95.7, P < .001; I² = 76.823%, P = .005; Egger's test: intercept = –3.04, P = .10; Begg and Mazumdar test: τ = −0.67, P = .17). Furthermore, the overall incidence of MACEs was 3.7% (1.3‐10.4, P < .001; I² = 51.556%, P = .103; Egger's test: intercept = –1.98, P =  < .11; Begg and Mazumdar test: τ = −0.67, P = .17). Finally, mortality within 1 year was 5% (3.5‐7, P < .001; I² = 29.675%, P = .202; Egger's test: intercept = –0.91, P = .62; Begg and Mazumdar test: τ = −0.04, P = .88).

Conclusions

APADs do not seem to be correlated with a reduction of either neurological events or mortality. By contrast, these tools showed satisfactory one‐year graft patency and a low incidence of MACEs. Further research on this topic is warranted.

Clampless versus clamped coronary bypass grafting: does it make a difference?

PURPOSE OF REVIEW

The techniques of coronary artery bypass grafting (CABG) have evolved remarkably over the last two decades since the introduction of off-pump coronary artery bypass (OPCAB). This article focuses on the clinical outcomes of 'clampless' CABG strategies, that include OPCAB with a partial clamp, OPCAB with a proximal suture device, and aorta no-touch OPCAB.

RECENT FINDINGS

Observational studies have shown the superiority of OPCAB for preventing strokes and pulmonary complications. Conversely, recent large-scale randomized controlled trials (RCTs) have been unable to demonstrate the benefits of OPCAB. Because of these differing results across numerous studies, the debate about the overall superiority of OPCAB versus on-pump CABG remains controversial. However, the literature regarding the OPCAB technique with minimized manipulation of the aorta suggests this has likely benefits, especially for high-risk patients.

SUMMARY

Previous large RCTs did not focus on specific approaches of OPCAB or the importance of the experience of surgeons and institutions, and so further studies are needed. Observational studies and meta-analyses have indicated that improved outcomes can be achieved by applying specific OPCAB approaches according to each patient's characteristics.

Patency of Saphenous Vein Grafts Using the PAS-Port System During Coronary Artery Bypass Surgery

BACKGROUND

Several proximal anastomosis devices have been developed to shorten the time required for a proximal anastomosis and to avoid aortic cross-/side-clamping during coronary artery bypass grafting. This study retrospectively examined the patency of saphenous vein grafts (SVGs) using the PAS-Port System (Cardia Inc, Redwood City, CA).

METHODS

From 2004 to 2014, 451 patients underwent coronary artery bypass graft operations requiring at least 1 proximal anastomosis using a PAS-Port device. A total of 802 PAS-Port devices were used, and 95.0% (762 of 802) were implanted successfully. Among the successfully implanted anastomoses, 76.8% (585 of 762) were evaluated using coronary angiography or multidimensional computed tomography, or both. The evaluations were performed between postoperative days 4 and 3,182 (mean, 319 ± 624 days). The early (1 to 365 days) and the midterm to long-term (more than 366 days) occlusion rates were examined. A complete postoperative clinical course was recorded for 70.7% of the patients.

RESULTS

Overall, 93.8% (549 of 585) of the device-dependent SVGs were patent. The patency rates of device-dependent SVGs that were 1, 2, 3, 4, 5, 6, 7, and 8 years old were 90.1% ± 1.8%, 87.1% ± 2.3%, 86.1% ± 2.5%, 82.9% ± 3.3%, 80.6% ± 3.9%, 77.2% ± 5.0%, 77.2% ± 5.0%, and 70.2% ± 8.1%, respectively. The longest follow-up period was 3,182 days (8.7 years). The occlusion rate for device-dependent SVGs tended to decrease as the number of patients accumulated.

CONCLUSIONS

The PAS-Port system provided acceptable SVG patency and clinical outcome for the early and midterm to long-term. There may be a learning curve for the use of PAS-Port device that affects the device-dependent SVG patency.

Cerebrovascular Events After No-Touch Off-Pump Coronary Artery Bypass Grafting, Conventional Side-Clamp Off-Pump Coronary Artery Bypass, and Proximal Anastomotic Devices: A Meta-Analysis

Background

Off‐pump coronary artery bypass (OPCAB) has been shown to reduce the risk of neurologic complications as compared to coronary artery bypass grafting performed with cardiopulmonary bypass. Side‐clamping of the aorta while constructing proximal anastomoses, however, still carries substantial risk of cerebral embolization. We aimed to perform a comprehensive meta‐analysis of studies assessing 2 clampless techniques: aortic “no‐touch” and proximal anastomosis devices (PAD) for OPCAB.

Methods and Results

PubMed, CINAHL, CENTRAL, and Google Scholar databases were screened for randomized controlled trials and observational studies comparing “no‐touch” and/or PAD with side‐clamp OPCAB and reporting short‐term (≤30 days) outcomes: cerebrovascular accident and all‐cause mortality. A total of 18 studies (3 randomized controlled trials) enrolling 25 163 patients were included. Aortic “no‐touch” was associated with statistically lower risk of cerebrovascular accident as compared to side‐clamp OPCAB: risk ratio 95% CI: 0.41 (0.27–0.61); P<0.01; I²=0%. Event rates were 0.36% and 1.28% for “no‐touch” and side‐clamp OPCAB, respectively. No difference was seen between PAD and side‐clamp OPCAB: 0.71 (0.33–1.55); P=0.39; I²=39%. A trend towards increased 30‐day all‐cause mortality with PAD and no difference with “no‐touch” were observed when compared to side‐clamp OPCAB. In a subset analysis, “no‐touch” consistently reduced the risk of cerebrovascular accident regardless of patients’ baseline risk characteristics. A benefit with PAD was observed in low‐risk patients.

Conclusions

Aortic “no‐touch” technique was associated with nearly 60% lower risk of postoperative cerebrovascular events as compared to conventional side‐clamp OPCAB with effect consistent across patients at different risk.

Morphological Evaluation of Proximal Anastomosis by PAS-Port(®) System in Patients with Long-Term Patent Grafts

PURPOSE

We examined grafts employing for morphological analysis of early and long-term results on proximal anastomosis with the PAS-Port(®).

METHODS

One hundred and four patients treated by OPCAB with PAS-Port(®) were performed postoperative MDCT. Morphological evaluation of the proximal anastomotic region was classified into three groups (A; graft was anastomosed almost perpendicularly to the aortic wall, B; graft was same type A, but subsequently curved to form an acute angle with the aortic wall, C; graft take off acute angle with the aortic wall) evaluated on planar and sagittal sections.

RESULTS

One hundred twenty-six PAS-Port(®) were used. Patency rate was 99.0% at discharge, 94.7% at 1 year, and no blockages were detected thereafter in patients examined. The morphology rate was A 50.6%, B 15.3% and C 34.1% on planar sections, and A 58.8%, B 10.6% and C 30.6% on sagittal sections.

CONCLUSION

The morphological evaluation of grafts revealed the degree of freedom in graft design to be relatively high and long-term patency posed no particular problem even if the layout of the proximal anastomotic region involved a relatively acute angle. The PAS-Port(®) was considered to be a highly reliable device which performed appropriate proximal anastomosis and improved the patency of vein grafting to the aortic wall.

Five-year clinical outcome and patency rate of device-dependent venous grafts after clampless OPCAB with PAS-port automated proximal anastomosis: the PAPA Study

OBJECTIVE

To evaluate long-term clinical performance and angiographic patency of automated proximal venous anastomoses following clampless coronary artery bypass (C-CAB).

METHODS

Observational study in patients submitted for isolated C-CAB and at least one proximal aortosaphenous anastomosis performed with an automated connector (Cardica PAS-Port) including 152 consecutive patients (165 devices and 199 device-dependent distal anastomoses), with LVEF > 30% and saphenous vein diameter of 4-6 mm. Clinical follow-up was 96% complete (4101/4269 pt-months). Graft patency rate was assessed with 64-slice CT-scan or coronary angiography. Freedom from major adverse cardiac and cerebrovascular events (MACCE) was reported as actuarial probability with 95% confidence limits and venous graft patency as actual rate at every year interval.

RESULTS

Early operative mortality was 1.9%; incidence of neurologic injury was zero. Freedom from MACCE was 92.7 ± 2.1 at one year and 85.2 ± 4.8 at five years. The actual patency rate of device-dependent venous grafts was 90%, 85%, 84%, 84%, and 93% for one-, two-, three-, four-, and five-year-old grafts, respectively.

CONCLUSIONS

The device is a well-performing system for proximal anastomoses. The incidence of neurologic complications seems to be reduced with this clampless approach. The high patency rate is stable over time.

Anastomotic devices in coronary artery surgery: it is about the anastomosis?

Excellent long-term graft patency remains the primary goal of any surgical coronary revascularization procedure, irrespective of how the operation itself is performed. Inter- and intra-surgeon variability in the surgical technique and in the subsequent quality of the anastomosis have the potential to significantly impact not only on graft patency but also, as a result, on patient outcomes. Anastomotic devices, proximal and distal, can facilitate the creation of rapid, reproducible, compliant anastomoses, on- or off-pump, in potentially difficult-to-access areas, often through minimal-access incisions, potentially with neuro-protective benefits, and can thus mitigate some of the hazards inherent in manually constructing anastomoses in technically challenging or suboptimal conditions. We review the three most commonly employed anastomotic devices in adult cardiac surgical practice today.

The results of the enclose II proximal anastomotic device in 178 off-pump coronary artery bypass surgeries

OBJECTIVE

Enclose II is a new device for proximal coronary artery bypass anastomoses. We evaluated the safety and effectiveness of Enclose II in patients who underwent off-pump coronary artery bypass grafting (CABG).

METHODS

Enclose II was used for isolated off-pump CABG in 178 patients at six heart centers between October 2005 and December 2009. The preoperative characteristics of the patients, complications related to Enclose II, and early graft patency rates were examined.

RESULTS

A total of 222 proximal anastomoses were performed in 178 patients using Enclose II. Forty-four of these patients had two proximal anastomoses using this device. New cerebral infarction that arose in two patients (1.1%) was not related to Enclose II. No aortic injury occurred. The graft patency rate was 96.4% at 1 year after surgery.

CONCLUSIONS

Enclose II is a safe and useful assist device for proximal anastomoses in patients undergoing off-pump CABG.

Are surgical trials with negative results being interpreted correctly?

BACKGROUND

Many published accounts of clinical trials report no differences between the treatment arms, while being underpowered to find differences. This study determined how the authors of these reports interpreted their findings.

STUDY DESIGN

We examined 54 reports of surgical trials chosen randomly from a database of 110 influential trials conducted in 2008. Seven that reported having adequate statistical power (β ≥ 0.9) were excluded from further analysis, as were the 32 that reported significant differences between the treatment arms. We examined the remaining 15 to see whether the authors interpreted their negative findings appropriately. Appropriate interpretations discussed the lack of power and/or called for larger studies.

RESULTS

Three of the 7 trials that did not report an a priori power calculation offered inappropriate interpretations, as did 3 of the 8 trials that reported an a priori power < 0.90. However, we examined only a modest number of trial reports from 1 year.

CONCLUSIONS

Negative findings in underpowered trials were often interpreted as showing the equivalence of the treatment arms with no discussion of the issue of being underpowered. This may lead clinicians to accept new treatments that have not been validated.

Long-term follow-up of patients operated with the symmetry proximal connector device

OBJECTIVE

: The Symmetry proximal connector device was introduced as a facilitator for construction of proximal anastomosis in coronary bypass surgery. Use of the connector made it unnecessary to clamp the ascending aorta. Early results were promising, but a controlled study performed in our center demonstrated poor angiographic patency of saphenous veins attached with the connector. The objective of this study was to investigate long-term clinical results in patients operated with connector or traditional suture technique.

METHODS

: At a minimum of 5 years after surgery, medical records of 46 patients who had undergone off-pump coronary bypass with Symmetry (n = 23) or traditional suture (n = 23) were examined, and the patients were interviewed personally by phone. Patients were asked about the presence of angina pectoris, hospital admission for cardiac conditions, or the need for new interventions. The Norwegian population registry was used to document survival status.

RESULTS

: Two control patients and five Symmetry patients died during the observation period (P = 0.414). Seven Symmetry and one control patient required reintervention (P = 0.015). Of the patients who were interviewed, 8 of 19 Symmetry patients suffered from angina and none of 20 control patients (P = 0.003).

CONCLUSIONS

: Patients who were operated with the Symmetry connector device have a high chance of having cardiac ischemia in the intermediate to long term after surgery, despite of relatively frequent reintervention. Patients operated with this connector requires close clinical follow-up.

Management of patients with a calcified aorta or low ejection fraction undergoing multivessel coronary revascularization

Off-pump coronary artery bypass surgery (OPCAB) provides an alternative method of surgical revascularization by allowing coronary anastomoses to be constructed without the use of cardiopulmonary bypass and without manipulation of the aorta. The presence of a calcified aorta is one of the strongest indications for OPCAB because both distal and proximal anastomoses can be performed without cannulation or clamping of the aorta. In patients with left ventricular dysfunction, OPCAB techniques allow for revascularization without the need for global myocardial ischemia associated with cardioplegic arrest.

Sutureless proximal anastomosis using the PAS-Port system: six-month patency and five-year follow-up in "all-comers"

BACKGROUND

The PAS-Port system (Cardica, Inc, Redwood City, CA) was used routinely for patients undergoing coronary surgery with at least one venous graft. Graft patency and clinical results were evaluated, respectively, at 6 months and 5 years after surgery.

METHODS

A total of 100 patients (82 males, 18 females; mean age 68.9 ± 12 years) underwent coronary bypass surgery with at least one PAS-Port anastomosis (total number of PAS-Port implants: n = 117). At 6 months after surgery all patients were followed up clinically and 86 patients with 101 PAS-Port implants underwent either a multidetector computed tomographic scan or coronary angiography. Actuarial freedom from MACCE (major adverse cardiac and cerebrovascular events) was assessed at 5 years after surgery.

RESULTS

Six-month PAS-Port patency was 88%. The inner diameter of the graft at the implant site (measured in 26 patients) did not reveal any pathologic narrowing (mean inner diameter 3.1 ± 0.6 mm). At 5 years, freedom from overall MACCE was 79% ± 5% and freedom from PAS-Port target vessel revascularization was 94% ± 6%.

CONCLUSIONS

The routine use of PAS-Port was associated with good vein graft patency at 6 months and a low incidence of MACCE at 5 years after surgery. No evidence of implant-related graft stenosis was detected.

Cerebral Emboli Generation during Off-Pump Coronary Artery Bypass Grafting with a Clampless Device versus Partial Clamping of the Ascending Aorta

Objective

It is not known whether use of a clampless facilitating device during proximal graft anastamosis decreases intraoperative cerebral emboli in patients with mild atherosclerotic ascending aorta (AAA) having off-pump coronary artery bypass.

Methods

After intraoperative epiaortic ultrasound showed no more than mild (grade I–II) atherosclerotic ascending aorta, 20 patients were randomized to receive either partial clamping (PC, n = 10) or the HEARTSTRING clampless device (HS, n = 9) for proximal graft construction on the ascending aorta. Continuous transcranial Doppler monitoring, with capability to discern gaseous from solid particulates, was used intraoperatively to monitor high-intensity transient signals (HITS) in the middle cerebral arteries. Postoperative diffusion-weighted brain magnetic resonance imaging documented old and new ischemic brain lesions.

Results

There were no significant differences between the groups in the number of proximals (P = 0.14), distals (P = 0.4), or intraoperative cell saver transfusions (P = 0.69). The total number of HITS was not significantly different between the PC and HS groups (P = 0.2). However, the number of solid HITS was significantly lower in the HS than in the PC group (2.7 ± 2.6 versus 14.0 ± 8.1; P < 0.001). The number of gaseous emboli in the HS group was fourfold greater when a mister-blower rather than a suction device was used to clear blood away from the HS site. Postoperatively, there were no deaths, myocardial infarctions, or clinical strokes observed in either group. Diffusion-weighted cerebral magnetic resonance imaging revealed no statistical difference between groups for new infarct lesions.

Conclusions

Use of the HS device during off-pump coronary artery bypass was associated with significantly fewer intraoperative solid emboli in the middle cerebral artery than PC of the ascending aorta.

Use of skeletonized radial artery graft with the PAS-Port proximal anastomotic device

PURPOSE

We report our initial experience with the PAS-Port proximal anastomosis system (Cardica Inc, Redwood City, CA) using full-skeletonized radial artery (RA) in patients requiring off-pump coronary artery bypass grafting.

DESCRIPTION

The PAS-Port system (Cardica Inc) was used in 25 patients undergoing off-pump coronary artery bypass surgery. All patients received at least one RA graft using the PAS-Port system on the proximal anastomosis. The radial arteries were harvested in a fully skeletonized fashion before loading to the PAS-Port system.

EVALUATION

Our attempt to use the PAS-Port system for proximal anastomosis of the RA was successful in 25 anastomoses. Postoperative angiography showed 24 grafts to be widely patent. During the mean postoperative follow-up of 9.2 +/- 3.1 months, there was no cardiac-related event in any patient. Mid-term patency collected from the first 8 patients was 87.5% (mean follow-up, 12.8 +/- 2.8 months).

CONCLUSIONS

The PAS-Port system does not require aortic clamping and enables the creation of uniform and widely patent anastomosis with use of RA grafts.

The Current Status of Anastomotic Devices for Coronary Artery Bypass Surgery

The purpose of this article is to briefly review the history of proximal and distal anastomotic devices and to discuss presently available devices. Clinical outcome data from the EPIC Trial of the Cardica PAS-Port Proximal Anastomosis System will also be presented.