Management of Guidewire Entrapment and Fracture During Percutaneous Coronary Intervention: When All Bailout Techniques Fail!

A 55-year-old man presented with chest pain and was diagnosed with non-ST-segment elevation myocardial infarction. Coronary angiography revealed a 95% eccentric lesion in the mid-right coronary artery. After 3 intracoronary stents were placed, the guidewire became entrapped in 1 of the stents; multiple attempts at retrieval were unsuccessful. Ultimately, the guidewire fractured, and a coronary artery bypass graft surgery was performed to remove the guidewire fragments. This report reviews the procedural steps for wire retrieval that are critical for operators to avoid coronary artery bypass surgery.

Free-wall rupture of the myocardium following infarction: a changing clinical portrait in the reperfusion era: a case report

Free wall rupture of the myocardium is an important complication and major cause of death following acute transmural (ST segment elevation) myocardial infarction. Pathologic changes on a cellular level may combine with mechanical stressors to weaken the myocardium postinfarction. Risk factors for myocardial rupture include advanced age, female gender, prior hyper-tension, first myocardial infarction, late presentation, lack of collateral blood flow, and persisting chest pain and ST segment elevations. Thrombolytic therapy does not increase risk of rupture when given early in myocardial infarction, but late thrombolytic therapy may heighten risk. Primary percutaneous coronary intervention for acute myocardial infarction has reduced the incidence of myocardial rupture compared to thrombolytic therapy. This advantage likely can be ascribed to higher rates of immediate reperfusion with catheter techniques, as well as to the avoidance of thrombolytic-mediated hemorrhagic transformation of the infarction zone. Careful regulation of blood pressure and pulse using nitrates and beta-adrenergic blockers may mitigate the tendency toward myocardial rupture. Early and accurate diagnosis based on clinical and echocardiographic evidence can lead to successful surgical treatment.

Delayed operative intervention in the management of traumatic descending thoracic aortic rupture

BACKGROUND

Outcomes may be improved by purposefully delaying surgical intervention of the traumatically ruptured descending thoracic aorta.

METHODS

Fifty-seven patient records identified through the Trauma Registry of a level 1 trauma center between January 1993 and April 2002 were retrospectively analyzed between groups who underwent "clamp-and-sew" versus partial left heart bypass repair techniques and between emergent versus delayed repair.

RESULTS

Thirty-two (56%) of 57 patients were male. The mean age among survivors and nonsurvivors was 41 +/- 18 (range 13 to 70) and 52 +/- 23 (range 18 to 92; p = 0.04) years, and Injury Severity Score was 31 +/- 13 (range 17 to 75) and 40 +/- 16 (range 16 to 75; p = 0.04) points, respectively. Thirty-one (54%) underwent surgical intervention, 20 (35%) died during their initial resuscitation, and 6 (11%) were managed nonoperatively. Seventeen (55%) were repaired using partial left heart bypass and 14 (45%) using the clamp technique. Twenty-one (68%) had emergent repair and 10 (32%) had delayed repair. The rates of paraplegia, renal failure, and mortality were 12% (2 of 17), 0%, and 24% (4 of 17) in the bypass group, 0% (p = 0.29), 0%, and 36% (5 of 14, p = 0.36) in the clamp group, 9.5% (2 of 21), 0%, and 38% (8 of 21) in the emergent group (<24 hours after admission), and 0% (p = 0.45), 0%, and 10% (1 of 10, p = 0.12) in the delayed group (>24 hours after admission), respectively. Mean clamp times for the bypass and clamp groups were 44 +/- 18 (21 to 90) and 30 +/- 10 (14 to 52) minutes, respectively (p = 0.02). Overall operative mortality was 29% (9 of 31).

CONCLUSIONS

Purposefully delaying surgical intervention in selected cases of descending thoracic aortic rupture and using the clamp technique does not increase mortality or morbidity over immediate operation and use of partial left hear bypass.

Endovascular repair of abdominal aortic aneurysms in patients with congenital renal vascular anomalies

PURPOSE

The endovascular repair of abdominal aortic aneurysms (AAAs) has been suggested as an alternative to conventional aortic reconstruction. The presence of anomalous renal vascular anatomy frequently necessitates special planning during conventional aortic replacement and may also create unique challenges for endovascular repair. We analyzed our experience with 24 patients with variant renal vascular anatomies who underwent treatment with aortic endografts to determine the safety and efficacy of this technique in this population.

METHODS

During a 6-year period, 204 patients underwent aortic endograft procedures, 24 (11.8%) of whom had variations in renal vascular anatomy. There were 19 men and five women. Each of the 24 patients had variant renal vascular anatomy, which was defined by the presence of multiple renal arteries (n = 32), with or without a renal parenchymal anomaly (horseshoe or solitary pelvic kidney). Twenty patients underwent aneurysm repair with balloon expandable polytetrafluoroethylene grafts, and the remaining patients underwent endograft placement with self-expanding attachment systems. Eighteen patients underwent exclusion and presumed thrombosis of anomalous renal branches to effectively attach the aortic endograft. The decision to sacrifice a supernumerary artery was made on the basis of the vessel size (<3 mm), the absence of coexisting renal insufficiency, and the expectation for successful aneurysm exclusion.

RESULTS

The successful exclusion of the AAAs was achieved in all the patients, with the loss of a total of 17 renal artery branches in 12 patients. Small segmental renal infarcts (<20%) were detected in only six of the 12 patients with follow-up computed tomographic scan results, despite angiographic evidence of vessel occlusion at the time of endografting. No evidence of new onset hypertension or changes in antihypertensive medication was seen in this group. No retrograde endoleaks were detected through the excluded renal branches on late follow-up computed tomographic scans. Serum creatinine levels before and after endografting were unchanged after the exclusion of the AAA in all but one patient with multiple renal branches. One patient had a transient rise in serum creatinine level presumed to be caused by contrast nephropathy.

CONCLUSION

On the basis of this experience, we recommend the consideration of endovascular grafting for patients with AAAs and anomalous renal vessels when the main renal vascular anatomy can be preserved and when the loss of only small branches (<3 mm) is necessitated in patients with otherwise normal renal functions.

Increased intracerebral excitatory amino acids and nitric oxide after hypothermic circulatory arrest

BACKGROUND

Prolonged hypothermic circulatory arrest (HCA) results in neurologic injury, but the mechanism of this injury is unknown. This study was undertaken to measure quantitatively intracerebral excitatory amino acids and citrulline, an equal coproduct of nitric oxide, during HCA. We hypothesized that HCA resulted in higher levels of glutamate, aspartate, glycine, causing increased intracellular calcium, and therefore, nitric oxide and citrulline.

METHODS

Ten dogs underwent intracerebral microdialysis and 2 hours of HCA at 18 degrees C. Effluent was analyzed by high performance liquid chromatography with electrochemical detection. Five dogs each were sacrificed at 8 and 20 hours after HCA. Neuronal apoptosis was scored from 0 (no injury) to 100 (severe injury).

RESULTS

Time course of HCA was divided into six periods. Peak levels of amino acids in each period were compared with those at baseline. Glutamate, coagonist glycine, and citrulline, an equal coproduct of nitric oxide, increased significantly over baseline during HCA, cardiopulmonary bypass, and 2 to 8 hours after HCA. Aspartate increased significantly during HCA and 8 to 20 hours after HCA. Apoptosis score was 65.56 +/- 5.67 at 8 hours and 30.63 +/- 14.96 at 20 hours after HCA.

CONCLUSIONS

Our results provide direct evidence that HCA causes increased intracerebral glutamate and aspartate, along with coagonist glycine. We conclude that HCA causes glutamate excitotoxicity with subsequent nitric oxide production resulting in neurologic injury, which begins during arrest and continues until 20 hours after hypothermic circulation arrest. To provide effective cerebral protection, pharmacologic strategies to reduce glutamate excitotoxicity require intervention beyond the initial ischemic insult.

Neuronal nitric oxide synthase inhibition reduces neuronal apoptosis after hypothermic circulatory arrest

BACKGROUND

Neurologic injury, including choreoathetosis and learning and memory deficits, occurs after prolonged hypothermic circulatory arrest (HCA). Apoptosis, or programmed cell death, is a possible cause of the neurologic injury seen after HCA. However, the mechanism of apoptosis is unknown. Hypothermic circulatory arrest causes glutamate excitotoxicity, resulting in increased nitric oxide production. We therefore hypothesized that nitric oxide mediates apoptosis. The purpose of this study was to determine if neuronal nitric oxide synthase inhibition reduces neuronal apoptosis in an established canine model of HCA.

METHODS

Fourteen male hound dogs (weight, 20 to 27 kg) were placed on closed-chest cardiopulmonary bypass, subjected to 2 hours of HCA at 18 degrees C, rewarmed to normothermia, and sacrificed 8 hours after HCA. Group 1 (n = 7) dogs were treated with the neuronal nitric oxide inhibitor 7-nitroindazole, 25 mg/kg intraperitoneally, before arrest and every 2 hours until sacrifice. Group 2 (n = 7) dogs received vehicle only. The brains were analyzed histopathologically. Apoptosis, identified by hematoxylin-eosin staining, was confirmed by DNA terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end-labeling assay and electron microscopy. Apoptosis was scored by a blinded neuropathologist from 0 (normal) to 100 (severe injury).

RESULTS

Apoptosis occurred early after HCA in select neuronal populations, including the hippocampus, stria terminalis, neocortex, and entorhinal cortex. Apoptotic neurons showed a characteristic shrunken cytoplasm and nuclear chromatin condensation. 7-Nitroindazole significantly inhibited apoptosis (group 1 versus 2: 19.17 +/- 14.39 versus 61.11 +/- 5.41; p < .001).

CONCLUSIONS

Our results provide evidence that apoptosis is associated with the neurologic injury that occurs after HCA and that nitric oxide mediates the apoptosis that occurs after HCA. Strategies for cerebral protection during HCA may include the inhibition of neuronal nitric oxide synthase.