Atheroembolic Complications Research Articles

Impact of Aortic Atherosclerosis Burden on Outcomes of Surgical Aortic Valve Replacement

Epiaortic ultrasound detects and localizes ascending aortic atherosclerosis. In this analysis we investigated the association between epiaortic ultrasound-based atheroma grade during surgical aortic valve replacement (SAVR) and perioperative adverse outcomes. SAVR patients in a randomized trial of 2 embolic protection devices underwent a protocol-defined 5-view epiaortic ultrasound read at a core laboratory. Aortic atherosclerosis was quantified with the Katz atheroma grade, and patients were categorized as mild (grade I-II) or moderate/severe (grade III-V). Multivariable logistic regression was used to estimate associations between atheroma grade and adverse outcomes, including death, clinically apparent stroke, cerebral infarction on diffusion-weighted magnetic resonance imaging, delirium, and acute kidney injury (AKI) by 7and 30 days. Precannulation epiaortic ultrasound data were available for 326 of 383 randomized patients (85.1%). Of these, 106 (32.5%) had moderate/severe Katz atheroma grade at any segment of the ascending aorta. Although differences in the composite of death, stroke, or cerebral infarction on diffusion-weighted magnetic resonance imaging by 7 days were not statistically significant, moderate/severe atheroma grade was associated with a greater risk of AKI by 7 days (adjusted odds ratio, 2.63; 95% confidence interval, 1.24-5.58; P= .01). At 30 days, patients with moderate/severe atheroma grade had a greater risk of death, stroke, or AKI (adjusted odds ratio, 1.97; 95% confidence interval, 1.04-3.71; P= .04). Moderate/severe aortic atherosclerosis was associated with an increased risk of adverse events after SAVR. Epiaortic ultrasound may serve as a useful adjunct for identifying patients who may benefit from strategies to reduce atheroembolic complications during SAVR.

Proximal anastomosis in off pump coronary surgery patients with heavily calcified aorta

Maneuvers during coronary artery bypass (CAB) operations like cannulation, cross or partial clamping of ascending or arcus aorta must be avoided in the existence of significantly atherosclerotic plaques. If these maneuvers are performed, atherosclerotic plaques will be prone to be the reason of the atheroembolic complications due to debris dislocation. We present a simple, effective, and protective technique for constructing proximal anastomoses during off-pump CAB operations to prevent patients from devastating atheroembolic complications either cerebral or systemic.

EComment. Acute aortic dissection type A: which strategy of the arterial perfusion to choose?

We read with the great interest the report of Conzelmann and colleagues [1], describing the original method of direct aortic cannulation and we congratulate the authors for their excellent results. However, the separation between the adventitial layers of the ascending aorta and the pulmonary artery can lead to rupture of the aorta in this area. In addition, direct cannulation of the true aortic can be complicated by thromboembolism in the case of the false lumen thrombosis. Inadequate organ perfusion is one of the major problems in patients with acute type A aortic dissection (AADA). Until recently, the retrograde perfusion via the femoral artery was the perfusion mode of choice in thoracic aortic surgery [2]. But in some cases, this was marked by a high risk of potential malperfusion and atheroembolic complications associated with retrograde perfusion, especially in dissections. In recent years, subclavian artery cannulation for AADA has become a widely accepted arterial access for antegrade aortic and cerebral perfusion [3,4]. Surgical exposure of the subclavian artery is easy to perform, and if the operative field and the patient are routinely prepared for this procedure, it is rapidly performed. At our institute, 148 patients with AADA underwent surgery. As of 2004, we have been using the subclavian arterial perfusion in the majority of patients. This has led to a significant reduction in the incidence of postoperative multiple organ failure, and has reduced hospital mortality (from 24% to 8-10% in recent years). In our practice, surgical exposure and cannulation of subclavian artery usually require an additional 5-10 minutes, but in any case, it does not affect the outcome of the operation. We have rarely found heavily diseased subclavian arteries and involvement of a subclavian artery by the dissection process is also rare. In addition, the use of this technique facilitates the work of the surgeon at the expense of absence of arterial cannula in a working zone, as well as reduces the risk of embolic complications. All this, in our opinion, makes this method more preferable. However, in emergency situations with highly unstable haemodynamics or in case of dissections extending into the innominate artery, the method described by the authors may be useful [1]. In conclusion, we would like to note that the ascending aortic cannulation of the true lumen under direct vision deserves serious consideration as a safe and rapid way to ensure antegrade arterial perfusion in same unstable patients with acute type A dissection. However, this method requires further study.

Heparin during Diagnostic Cerebral Angiography, Is It Safe? (P05.253)

Objective: This study aimes at identifying the safety of different techniques in administering heparin during diagnostic cerebral angiography (DCA). Background Unfractionated heparin is commonly used during DCA to reduce thromboembolic complications. In heparin insensitive patients, pressurized heparinized saline is always connected to the arterial sheath. Further heparin bolus for DCA is employed by few interventionalist. We sought to identify if these different techniques impact outcomes. Design/Methods: We reviewed all DCA procedures in our database for the past 2 years. We excluded procedures which were immediately followed by neurointervention, spinal angiograms, and cases with insufficient documentation. Procedures divided into 3 groups, those received heparinized flush for the femoral artery sheath; those who received additional intravenous heparin bolus (3000-5000 IU); and those who had a second heparinized saline flush for the diagnostic catheter. Endpoints included any atheroembolic complications and serious groin complications (bleeding requiring a transfusion, retroperitoneal hemorrhage, or femoral artery tear requiring vascular repair). Results: The final cohort included 1143 DCA performed on 959 patients. Among those 1037 patients had heparinized saline flush for the groin sheath; 62 patients had received additional intravenous heparin bolus; and 44 patients had 2 heparinized flush lines without heparin bolus. The incidence of any atheroembolic complications occurred in 7 patients (0.6%) and any serious groin complications in 6 patients (0.5%). All of these complications occurred in those who had heparinized saline for the arterial sheath only compared to the other groups (P > 0.05). Conclusions: At our institution, the incidence of any complications with DCA was low. Furthermore, there was no statistical evidence that administration of intravenous heparin bolus or a second heparinized saline line would increased serious groin bleeding or cause less atheroembolic complications. Disclosure: Dr. Kitchener has nothing to disclose. Dr. Amer has nothing to disclose. Dr. Kaushal has nothing to disclose. Dr. Bienemann has nothing to disclose. Dr. Callison has nothing to disclose. Dr. Vora has nothing to disclose. Dr. Edgell has nothing to disclose.

The Pathophysiology of Cardiac Surgery-Associated Acute Kidney Injury (CSA-AKI)

Cardiac surgery associated acute kidney injury (CSA-AKI) is a significant clinical problem. Its pathogenesis is complex and multifactorial. It likely involved at least six major injury pathways: exogenous and endogenous toxins, metabolic factors, ischemia and reperfusion, neurohormonal activation, inflammation and oxidative stress. These mechanisms of injury are likely to be active at different times with different intensity and probably act synergistically. Because of such complexity and the small number of randomised controlled investigations in this field only limited recommendations can be made. Nonetheless, it appears important to avoid nephrotoxic drugs and desirable to avoid hyperglycemia in the peri-operative period. The duration of cardiopulmonary bypass should be limited whenever possible. Off-pump surgery, when indicated, may decrease the risk of AKI. Invasive hemodynamic monitoring focussed on attention to maintaining euvolemia, an adequate cardiac output and an adequate arterial blood pressure is desirable. Echocardiography may be useful in minimizing atheroembolic complications. The administration of N-acetylcysteine to protect the kidney from oxidative stress is not recommended. There is marked lack of randomised controlled trials in this field.

Predictors of Atheroembolic Complications During Saphenous Vein Graft Percutaneous Coronary Intervention

Predictors of Atheroembolic Complications During Saphenous Vein Graft Percutaneous Coronary Intervention

Hypothermic Circulatory Arrest Enables Aortic Valve Replacement in Patients With Unclampable Aorta

Atheroembolic complications associated with clamping a severely diseased ascending aorta during aortic valve replacement may result in unacceptable mortality and morbidity. Different management options include hypothermic circulatory arrest to replace the aortic valve, an aortic endarterectomy, or tube graft replacement of the aorta to allow safe application of cross-clamp before aortic valve replacement. From 1998 to 2004, 70 patients who underwent aortic valve replacement had an aorta that was unclampable. Median age was 76 years; 33 (47%) were women; 46 (66%) had concomitant coronary artery bypass grafting; 9 (13%) had concomitant mitral valve surgery; and 4 (6%) were reoperations. Hypothermic circulatory arrest was used to replace the aortic valve alone, to do an aortic endarterectomy, or replace the ascending aorta with a tube graft. Operative mortality was 4%. There were 8 (11%) strokes and 1 (1.4%) transient ischemic attack. Statistical analysis showed no association between circulatory arrest period and occurrence of adverse cerebral events. There was no significant difference among the three groups when operative mortality and cerebral events were compared. Hypothermic circulatory arrest is an important adjunct that allows aortic valve replacement to be performed with an acceptable mortality but with an increased risk of cerebral event in this high-risk and elderly group of patients.

Evaluation of the Enclose Proximal Anastomosis Device in Coronary Artery Bypass Grafting

Minimal manipulation of the ascending aorta during coronary artery bypass grafting may reduce the incidence of adverse perioperative events related to atheroembolic events. The objective of this study was to evaluate a new proximal anastomotic device (Novare Enclose device [Novare Surgical Systems, Cupertino, CA]). Over a 23-month period, a total of 76 proximal anastomoses were performed in 50 patients (40 males and 10 females; mean age, 74.36 years). In 45 patients, the proximal anastomosis was constructed before the distal (25 off-pump and 20 on-pump), and in 5 patients the proximal anastomosis was constructed on cardiopulmonary bypass because of diseased ascending aortas. The average time per anastomosis was <8 minutes. There were no device related complications. There were no atheroembolic complications in this cohort of patients. One patient underwent cardiac catheterization postoperatively, and the proximal vein anastomosis in this patient was widely patent. The Novare Enclose proximal anastomotic device (Novare Surgical Systems) appears to be safe and effective as a tool for proximal anastomosis within a reasonable time period and is comparable with accepted techniques.

Improved hydrodynamics of a new aortic cannula with a novel tip design.

Reduction of atheroembolic complications during cardiopulmonary bypass remains a major challenge in cardiac surgery. New cannula tip designs may help to attenuate this problem by improved hydrodynamics. Pressure gradients and back pressures of a new aortic cannula tip design were measured and compared with the Medos X-Flow, Sarns Soft-Flow and Argyle THI cannulae at various flow rates in a mock circulation followed by flow visualization. Pressure gradients were the lowest for the new cannula. Back pressures of the new cannula were up to 84% lower than for the Argyle cannula. The back pressure profile and flow visualization of the new cannula showed broad centric flow dispersion with a transcannula increase of flow area from 38 mm2 to 139 mm2. The new design of an aortic cannula tip provides improved hydrodynamics, with low pressure gradients, low back pressures and a uniform central dispersion of flow, reducing the sandblasting effect.

Reduced strokes in the elderly: the benefits of untouched aorta off-pump coronary surgery

Background Avoiding aortic manipulation during off-pump coronary artery bypass (OPCAB) reduces the risk for atheroembolic complications and may, thus, benefit elderly patients who are prone to atherosclerotic aortic involvement. Methods During a period of 18 months (2000–2002), 160 consecutive OPCAB patients older than 75 years were evaluated. One hundred and three patients undergoing clampless OPCAB were compared to 57 patients in whom side clamps were applied. Clampless revascularization was achieved by in situ or T-graft arterial configurations. Results Mean age was older (79.3 years vs 78.2, p = 0.049) and the prevalence (43% vs 7%, p < 0.0001) and severity of aortic disease was higher in the clampless group. The main conduits used were bilateral skeletonized internal thoracic artery (47%) and radial arteries (42%). More grafts were performed in the side-clamp group (2.5 ± 0.5 vs 2.3 ± 0.6, p = 0.023), however, revascularization of the postero-lateral territory was com-parable. While early mortality (2.9% vs 7%, p = ≥0.05), perioperative myocardial infarction (3% vs 5%, p = ≥0.05), and sternal infections (none) were similar, the incidence of major neurological complications (0% vs 5.3%, p = 0.044) and the combined outcome of stroke or mortality (3% vs 12%, p = 0.035) were lower in the clampless group. Multivariate analysis identified side clamping as a predictor for the occurrence of stroke or mortality (OR, 6.28, CL 1.39–28.4, p = 0.017), increasing this risk by sixfold. Conclusions Clampless OPCAB is associated with reproducible neurological benefit. Improved neurological outcome may be conferred irrespective of the method of aortic screening in patients 75 years or older. The use of arterial conduits for this purpose is feasible despite the patients' advanced years.

Late Complication of Aortoiliac Stent Placement— Atheroembolization of the Lower Extremities

Background. Atheroembolization following aortoiliac stent placement is uncommon. The purpose of this study was to examine the management and risk factors of lower extremity atheroembolization following aortoiliac stent placement for occlusive disease.Materials and methods. From March 1993 to February 2001, the hospital records of all patients who developed thromboembolic events following aortoiliac stent placement were reviewed. Risk factor analysis was performed by comparing with the control group, which consisted of 493 patients treated with aortoiliac stents during the study period who did not develop atheroembolic complications. Patients with cardiac etiologies or aortic aneurysms as the source of embolization as well as those who developed acute embolization following stent deployment (<30 days) were excluded.Results. Atheroembolization occurred in eight patients (12 iliac artery stents and 1 aortic stent) at intervals ranging from 9 to 43 months (mean 22 months) following aortoiliac stent placement. Arteriography in all patients implicated the stented artery as the source of atheroembolism. Five corrective operations (two aorto-bifemoral bypasses, one ileofemoral bypass, and two aortoiliac endarterectomies) along with two concomitant femoropopliteal thrombectomies were performed successfully in five patients. The remaining three patients were treated with either thrombolysis and/or additional stent placement, which resulted in either iliac occlusion or recurrent embolic symptoms (P < 0.05). All 3 patients subsequently underwent bypass procedures (one ileofemoral and two femorofemoral bypasses). There was no perioperative mortality. During a mean follow-up of 16 months (range 3 to 45 months), two patients required minor amputations, whereas one required major leg amputation. No further episodes of atheroembolism occurred in the involved limbs following surgical bypass procedures. Risk factor analysis failed to identify potential variables that correlated with atheroembolism following aortoiliac stent placement.Conclusion. Patients with atheromatous embolization following aortoiliac stent placement should be evaluated aggressively. The treatment of choice is surgical correction or bypass with exclusion of the offending embolic source. Although intra-arterial stent placement in the atheroembolic stented iliac artery is feasible, it may provide a less durable result.

Microvascular complications of diabetes: the role of angiotensin converting enzyme inhibitors Proceedings of a Round Table Meeting, June 1999, San Diego, USA

Microvascular complications of diabetes: the role of angiotensin converting enzyme inhibitors Proceedings of a Round Table Meeting, June 1999, San Diego, USA

Intraoperative Transesophageal Echocardiography and Epiaortic Ultrasound for Assessment of Atherosclerosis of the Thoracic Aorta

Objectives. This study sought to determine the role of transesophageal echocardiography (TEE) and epiaortic ultrasound in the detection of atherosclerosis of the ascending aorta in patients undergoing cardiac surgery.Background. Atherosclerosis of the ascending aorta is a major risk factor for perioperative stroke and systemic embolism in patients undergoing cardiac surgery.Methods. Forty-four patients underwent prospective evaluation of the ascending aorta with two ultrasound techniques—epiaortic ultrasound and biplane TEE—and by palpation. The severity of atherosclerosis was graded on a four-point scale as normal, mild, moderate or severe.Results. A comparison of results with biplane TEE and those with epiaortic ultrasound yielded a kappa value of 0.12 (95% confidence interval 0 to 0.25), indicating poor correlation between the two. Compared with epiaortic ultrasound, biplane TEE significantly underestimated the severity of ascending aortic atherosclerosis, and this underestimation was more marked in the distal ascending aorta (p < 0.0001). When compared with epiaortic ultrasound and biplane TEE, palpation of the ascending aorta significantly underestimated the presence and severity of atherosclerosis (p < 0.0001 for both).Conclusions. Epiaortic ultrasound is more accurate than TEE for identification of atherosclerosis of the ascending aorta, but both ultrasound techniques are superior to palpation. Epiaortic ultrasound and TEE provide complementary information regarding thoracic aortic atherosclerosis. Modification of surgical technique on the basis of results of intraoperative epiaortic ultrasound and TEE in elderly patients undergoing cardiac procedures may prevent atheroembolic complications.

Avoiding Complications in Arterial Surgery

Our approach to vascular surgery is to recognize and contemplate perioperative complications and devise strategies to avoid them. These strategies are detailed in several of the major areas of arterial surgery. It is far easier to avoid complications than to deal with them when they occur. This is especially true for some complications in vascular surgery, such as intraoperative or postoperative cerebrovascular accident, atheroembolic complications, or distal thrombosis in lower-extremity reconstruction, that may result in either irreversible morbidity or death.