2022 ACC/AHA guideline for the diagnosis and management of aortic disease: A report of the American Heart Association/American College of Cardiology Joint Committee on Clinical Practice Guidelines

AIM

The "2022 ACC/AHA Guideline for the Diagnosis and Management of Aortic Disease" provides recommendations to guide clinicians in the diagnosis, genetic evaluation and family screening, medical therapy, endovascular and surgical treatment, and long-term surveillance of patients with aortic disease across its multiple clinical presentation subsets (ie, asymptomatic, stable symptomatic, and acute aortic syndromes).

METHODS

A comprehensive literature search was conducted from January 2021 to April 2021, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Library, CINHL Complete, and other selected databases relevant to this guideline. Additional relevant studies, published through June 2022 during the guideline writing process, were also considered by the writing committee, where appropriate.

STRUCTURE

Recommendations from previously published AHA/ACC guidelines on thoracic aortic disease, peripheral artery disease, and bicuspid aortic valve disease have been updated with new evidence to guide clinicians. In addition, new recommendations addressing comprehensive care for patients with aortic disease have been developed. There is added emphasis on the role of shared decision making, especially in the management of patients with aortic disease both before and during pregnancy. The is also an increased emphasis on the importance of institutional interventional volume and multidisciplinary aortic team expertise in the care of patients with aortic disease.

2022 ACC/AHA Guideline for the Diagnosis and Management of Aortic Disease: A Report of the American Heart Association/American College of Cardiology Joint Committee on Clinical Practice Guidelines

AIM

The "2022 ACC/AHA Guideline for the Diagnosis and Management of Aortic Disease" provides recommendations to guide clinicians in the diagnosis, genetic evaluation and family screening, medical therapy, endovascular and surgical treatment, and long-term surveillance of patients with aortic disease across its multiple clinical presentation subsets (ie, asymptomatic, stable symptomatic, and acute aortic syndromes).

METHODS

A comprehensive literature search was conducted from January 2021 to April 2021, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Library, CINHL Complete, and other selected databases relevant to this guideline. Additional relevant studies, published through June 2022 during the guideline writing process, were also considered by the writing committee, where appropriate. Structure: Recommendations from previously published AHA/ACC guidelines on thoracic aortic disease, peripheral artery disease, and bicuspid aortic valve disease have been updated with new evidence to guide clinicians. In addition, new recommendations addressing comprehensive care for patients with aortic disease have been developed. There is added emphasis on the role of shared decision making, especially in the management of patients with aortic disease both before and during pregnancy. The is also an increased emphasis on the importance of institutional interventional volume and multidisciplinary aortic team expertise in the care of patients with aortic disease.

2022 ACC/AHA Guideline for the Diagnosis and Management of Aortic Disease: A Report of the American Heart Association/American College of Cardiology Joint Committee on Clinical Practice Guidelines

AIM

The "2022 ACC/AHA Guideline for the Diagnosis and Management of Aortic Disease" provides recommendations to guide clinicians in the diagnosis, genetic evaluation and family screening, medical therapy, endovascular and surgical treatment, and long-term surveillance of patients with aortic disease across its multiple clinical presentation subsets (ie, asymptomatic, stable symptomatic, and acute aortic syndromes).

METHODS

A comprehensive literature search was conducted from January 2021 to April 2021, encompassing studies, reviews, and other evidence conducted on human subjects that were published in English from PubMed, EMBASE, the Cochrane Library, CINHL Complete, and other selected databases relevant to this guideline. Additional relevant studies, published through June 2022 during the guideline writing process, were also considered by the writing committee, where appropriate.

STRUCTURE

Recommendations from previously published AHA/ACC guidelines on thoracic aortic disease, peripheral artery disease, and bicuspid aortic valve disease have been updated with new evidence to guide clinicians. In addition, new recommendations addressing comprehensive care for patients with aortic disease have been developed. There is added emphasis on the role of shared decision making, especially in the management of patients with aortic disease both before and during pregnancy. The is also an increased emphasis on the importance of institutional interventional volume and multidisciplinary aortic team expertise in the care of patients with aortic disease.

Endovascular management of acute limb ischemia

Acute limb ischemia (ALI) is defined as a sudden decrease (<14 days) in limb perfusion causing a potential threat to limb viability. Endovascular treatment of ALI is an effective and appropriate primary treatment strategy in patients with a viable acutely ischemic limb due to a recent arterial occlusion. We present a case of acute limb ischemia and discuss percutaneous interventional treatment strategies including catheter-directed thrombolysis, rheolytic thrombectomy, and utilization of distal protection devices.

Carotid artery stenting: patient, lesion, and procedural characteristics that increase procedural complications

From the earliest experiences with carotid artery stenting (CAS) presumptive high risk features have included thrombus-containing lesions, heavily calcified lesions, very tortuous vessels, and near occlusions. In addition patients have been routinely excluded from CAS trials if they have contra-indications to dual antiplatelet therapy (aspirin and thienopyridines), a history of bleeding complications and severe peripheral arterial disease (PAD) making femoral artery vascular access difficult. Variables that increase the risk of CAS complications can be attributed to patient characteristics, anatomic or lesion features, and procedural factors. Clinical features such as older age (≥80 years), decreased cerebral reserve (dementia, multiple prior strokes, or intracranial microangiopathy) and angiographic characteristics such as excessive tortuosity (more than two 90° bends within 5 cm of the target lesion) and heavy calcification (concentric calcification ≥ 3 mm in width) have been associated with increased CAS complications. Other high risk CAS features include those that prolong catheter or guide wire manipulation in the aortic arch, make crossing a carotid stenosis more difficult, decrease the likelihood of successful deployment or retrieval of an embolic protection device (EPD), or make stent delivery or placement more difficult. Procedure volume for the operator and the catheterization laboratory team are critical elements in reducing the risk of the procedure. In this article, we help CAS operators better understand procedure risk to allow more intelligent case selection, further improving the outcomes of this emerging procedure.

A simple percutaneous technique for hemostasis and closure after transcatheter aortic valve implantation

Access closure is a key element to successful retrograde percutaneous transfemoral transcatheter aortic valve implantation. It requires large-bore femoral arterial access (18Fr-28Fr) which most operators manage with surgical access and closure under general anesthesia. We report a case example of how, using our center's peripheral interventional experience, we have developed a simple five step technique to achieve hemostasis percutaneously.

A randomized trial of intravenous n-acetylcysteine to prevent contrast induced nephropathy in acute coronary syndromes

BACKGROUND

Pharmacokinetic data suggests that the intravenous form of n-acetylcysteine (NAC) may be more effective than the oral formulation in preventing contrast induced nephropathy (CIN). NAC owing to its anti-oxidant properties might be beneficial for patients with acute coronary syndromes (ACS) who are at increased risk for CIN. The aim of this prospective randomized, single-center, double-blind, placebo controlled trial (NCT00939913) was to assess the effect of high-dose intravenous NAC on CIN in ACS patients undergoing coronary angiography and/or percutaneous coronary intervention (PCI).

METHODS

We randomized 398 ACS patients scheduled for diagnostic angiography ± PCI to an intravenous regimen of high-dose NAC (1,200 mg bolus followed by 200 mg/hr for 24 hr; n = 206) or placebo (n = 192). The primary end-point was incidence of CIN defined as an increase in serum creatinine concentration ≥ 25% above the baseline level within 72 hr of the administration of intravenous contrast.

RESULTS

There was no difference found for the primary end point with CIN in 16% of the NAC group and in 13% of the placebo group (p = 0.40). Change in serum cystatin-C, a sensitive marker for renal function, was 0.046 ± 0.204 in the NAC group and 0.002 ± 0.260 in the control group (p = 0.07).

CONCLUSION

In ACS patients undergoing angiography ± PCI, high-dose intravenous NAC failed to reduce the incidence of CIN.

Factors related to a clinically silent peri-procedural drop in hemoglobin with coronary and peripheral vascular interventions

Clinically evident and subclinical peri-procedural bleeding following interventional therapies are associated with adverse cardiovascular outcomes. The risk factors for clinically evident bleeding have been well described. Despite the well-documented association of adverse outcomes for patients with a subclinical peri-procedural hemoglobin drop, the clinical predictors have not yet been defined. We identified 1176 consecutive patients with a subclinical drop in hemoglobin (fall of ≥ 1 g/dl in patients without clinical bleeding) following percutaneous coronary interventions (PCI) and peripheral vascular interventions (PVI). Multivariate logistic regression analysis was performed. A subclinical peri-procedural hemoglobin drop ≥ 1 g/dl was identified in 41% (400/972) of PCI and in 49% (213/435) of PVI. More than one access site predicted a higher risk of a subclinical drop in hemoglobin in both groups. A body mass index ≥ 30 predicted a lower risk of a subclinical drop in hemoglobin in both groups. For PCI, creatinine clearance < 60 ml/min was associated with a higher risk of a subclinical drop in hemoglobin. In conclusion, clinically silent peri-procedural hemoglobin fall ≥ 1 g/dl is common in patients undergoing both coronary and peripheral percutaneous intervention. Predictors identified in our study will need prospective validation.

Catheter-based therapy of common femoral artery atherosclerotic disease

The objective of this paper is to describe outcomes of endovascular therapy in patients with symptomatic common femoral artery (CFA) lesions. Symptomatic atherosclerotic disease of the common femoral artery is an uncommon clinical entity, and there is no consensus regarding the suitability of catheter-based therapy. We reviewed the records of 26 consecutive patients treated with catheter-based therapy for symptomatic CFA lesions between 1994 and 2009. Angiographic success and procedure success were obtained in all vessels and in all patients. At 1 year, 100% (16/16) of the claudication patients and 70% (7/10) of the critical limb ischemia (CLI) patients maintained clinical success. The ankle— brachial index (ABI) significantly improved from a baseline of 0.47 ± 0.18 to 0.77 ± 0.18 ( p < 0.001) after the procedure. At their most recent clinic visit (31 months ± 14 months), clinical success was maintained in 100% of the claudication patients and in 70% (7/10) of the CLI patients. During the follow-up period, femoral vascular access for an unrelated procedure was obtained through the CFA stent. In conclusion, patients with symptomatic CFA atherosclerotic disease obtained excellent clinical outcomes with angioplasty with stenting. We found that angioplasty with stenting of the CFA did not preclude future CFA vascular access. Our data suggest that catheter-based therapies should be considered as an option to open surgery in selected patients with symptomatic CFA disease.

Nitinol stent implantation versus balloon angioplasty for lesions in the superficial femoral artery and proximal popliteal artery: twelve-month results from the RESILIENT randomized trial

BACKGROUND

Controversy still exists regarding the best endovascular treatment strategy for patients with symptomatic disease of the superficial femoral artery. There are conflicting data regarding the benefits of superficial femoral artery stenting and the role of primary stenting compared with balloon angioplasty with provisional stent implantation.

METHODS AND RESULTS

A total of 206 patients from 24 centers in the United States and Europe with obstructive lesions of the superficial femoral artery and proximal popliteal artery and intermittent claudication were randomized to implantation of nitinol stents or percutaneous transluminal angioplasty. The mean total lesion length was 71 mm for the stent group and 64 mm for the angioplasty group. Acute lesion success (<30%residual stenosis) was superior for the stent group compared with the angioplasty group (95.8% versus 83.9%; P<0.01). Twenty-nine (40.3%) patients in the angioplasty group underwent bailout stenting because of a suboptimal angiographic result or flow-limiting dissection. Bailout stenting was treated as a target lesion revascularization and loss of primary patency in the final analysis. At 12 months, freedom from target lesion revascularization was 87.3% for the stent group compared with 45.1% for the angioplasty group (P<0.0001). Duplex ultrasound-derived primary patency at 12 months was better for the stent group (81.3% versus 36.7%; P<0.0001). Through 12 months, fractures occurred in 3.1% of stents implanted. No stent fractures resulted in loss of patency or target lesion revascularization.

CONCLUSIONS

In this multicenter trial, primary implantation of a self-expanding nitinol stent for moderate-length lesions in the superficial femoral artery and proximal popliteal artery was associated with better acute angiographic results and improved patency compared with balloon angioplasty alone.

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT00673985.

Endovascular stenting for vertebral artery stenosis

OBJECTIVES

The aim of this study was to demonstrate the safety and long-term durability of catheter-based therapy for symptomatic vertebral artery stenosis (VAS).

BACKGROUND

Symptomatic VAS carries with it a 5-year 30% to 35% risk of stroke. The 2-year mortality approaches 30% for medically managed strokes involving the posterior circulation. Surgical bypass is rarely performed, due to high morbidity and mortality. Endovascular revascularization with primary stenting offers an attractive treatment option for these patients.

METHODS

One-hundred five consecutive symptomatic patients (112 arteries, 71% male) underwent stent placement for extracranial (91%) and intracranial (9%) VAS from 1995 to 2006. Fifty-seven patients (54%) had bilateral VAS, 71 patients (68%) had concomitant carotid disease, and 43 patients (41%) had a prior stroke.

RESULTS

Procedural and clinical success was achieved in 105 (100%) and 95 (90.5%) patients, respectively. One-year follow-up was obtained in 87 (82.9%) patients, of which 69 patients (79.3%) remained symptom-free. At 1 year, 6 patients (5.7%) had died and 5 patients (5%) had a posterior circulation stroke. Target vessel revascularization occurred in 7.4% at 1 year. At a median follow-up of 29.1 months (interquartile range 12.8 to 50.9 months), 13.1% underwent target vessel revascularization, 71.4% were alive, and 70.5% remained symptom-free.

CONCLUSIONS

In experienced hands, stenting for symptomatic VAS can be accomplished with a very high success rate (100%), with few periprocedural complications, and is associated with durable symptom resolution in the majority (approximately 80%) of patients. We conclude that endovascular stenting of vertebral artery atherosclerotic disease is safe and effective compared with surgical controls and should be considered first-line therapy for this disease.

Acute stroke intervention by interventional cardiologists

OBJECTIVES

To report the technical success and clinical outcomes of catheter-based therapy (CBT) for acute ischemic stroke in patients ineligible for intravenous thrombolysis.

BACKGROUND

Acute ischemic stroke is common but undertreated. CBT for acute ischemic stroke is a therapeutic option in selected patients who are not candidates for intravenous thrombolysis.

METHODS

Consecutive stroke patients who were ineligible for intravenous thrombolysis and underwent CBT were identified by retrospective chart review. Demographic information, National Institutes of Health Stroke Scale (NIHSS), procedural characteristics, and clinical outcomes during hospitalization and at 90 days follow up were collected. Experienced interventional cardiologists with the consultative support of stroke neurologists were on call for acute strokes.

RESULTS

A total of 33 acute ischemic stroke patients underwent emergency cerebral angiography, with 26 patients undergoing CBT. Successful "culprit" artery recanalization was achieved in 23 (88%) of the 26 patients. In-hospital adverse events occurred in 4 (15%) patients, with intracerebral hemorrhage (ICH) (12%) representing the most common adverse event. The baseline NIHSS for patients who underwent intervention was 16.5 +/- 9.9 (median 16) and improved significantly to 9.9 +/- 8.7 (median 9) (P < 0.001) at hospital discharge. A modified Rankin score of two or less (indicating mild disability) was achieved in half (n = 13) of the CBT treated patients. All cause mortality at 90 days was 8% (2/26).

CONCLUSIONS

In selected patients, CBT provided by qualified interventional cardiologists supported by stroke neurologists, offers a safe and effective option for patients with acute stroke who are not eligible for intravenous thrombolysis.

Techniques for acute stroke intervention

Stroke or cerebrovascular accident is the second most common cause of death in Western countries. Although stroke is a treatable disease, the majority of patients do not receive intravenous thrombolysis or catheter-based therapy. The lack of treatment is multifactorial. Several treatments have been studied. Research and development in the area of acute stroke treatment are ongoing.

Carotid artery stent placement is safe in the very elderly (> or =80 years)

BACKGROUND

Carotid artery stent (CAS) placement is an alternative to carotid endarterectomy (CEA) for stroke prevention. Clinical adoption of CAS depends on its safety and efficacy compared to CEA. There are conflicting reports in the literature regarding the safety of CAS in the elderly. To address these safety concerns, we report our single-center 13-year CAS experience in very elderly (> or =80 years of age) patients.

METHODS

Between 1994 and 2007, 816 CAS procedures were performed at the Ochsner Clinic Foundation. Very elderly patients, those > or =80 years of age, accounted for 126 (15%) of all CAS procedures. Independent neurologic examination was performed before and after the CAS procedure.

RESULTS

The average patient age was 82.9 +/- 2.9 years. Almost one-half (44%) were women and 40% were symptomatic from their carotid stenoses. One-third of the elderly patients met anatomic criteria for high surgical risk as their indication for CAS. The procedural success rate was 100% with embolic protection devices used in 50%. The 30-day major adverse coronary or cerebral events (MACCE) rate was 2.7% (n = 3) with all events occurring in the symptomatic patient group [death = 0.9% (n = 1), myocardial infarction = 0%, major (disabling) stroke = 0.9% (n = 1), and minor stroke = 0.9% (n = 1)].

CONCLUSION

Elderly patients, > or =80 years of age, may undergo successful CAS with a very low adverse event rate as determined by an independent neurological examination. We believe that careful case selection and experienced operators were keys to our success.

Diabetes mellitus does not preclude stabilization or improvement of renal function after stent revascularization in patients with kidney insufficiency and renal artery stenosis

OBJECTIVE

To assess the impact of stent revascularization on the renal function of diabetic and nondiabetic patients with renal insufficiency.

BACKGROUND

Renal artery revascularization has been shown to stabilize or improve renal function in patients with significant renal artery stenosis and impaired renal function. However, some studies have suggested negligible or no benefit of renal function in diabetic patients with the same condition.

METHODS

We retrospectively compared data from 50 consecutive patients undergoing renal artery stent placement with renal insufficiency (serum creatinine > or = 1.5-4.0 mg/dl) and global ischemia (bilateral or solitary [single] kidney renal artery stenosis) There were 17 diabetic (DM) and 33 nondiabetic (NDM) patients. The endpoints included the follow-up measurements of renal function, blood pressure, and number of antihypertensive medications.

RESULTS

After stent placement, at a mean follow-up of 42 +/- 18 months (range: 6-62 months), 79% NDM (N = 26), and 76% DM patients (N = 13) (P = NS) had improvement in the slope of the reciprocal of creatinine (1/SCr), indicating a beneficial effect in renal function in many patients.

CONCLUSION

Renal artery stent placement appears to be equally beneficial in preserving renal function in DM and NDM patients with ischemic nephropathy and global renal ischemia.

Endovascular therapy for chronic mesenteric ischemia

OBJECTIVES

We sought to describe the outcomes of a consecutive series of patients with chronic mesenteric ischemia (CMI) who were treated with percutaneous stent revascularization.

BACKGROUND

Historically, the treatment for CMI has been surgical revascularization. However, surgery carries a significant procedural complication rate and mortality.

METHODS

Fifty-nine consecutive patients with CMI underwent stent placement in 79 stenotic (>70%) mesenteric arteries. All patients had clinical follow-up and 90% had anatomical follow-up with angiography (computed tomography or conventional) or ultrasound at > or =6 months after the procedure.

RESULTS

Procedural success was obtained in 96% (76 of 79 arteries) and symptom relief occurred in 88% (50 patients). At a mean follow-up of 38 +/- 15 months (range, 6 to 112 months), 79% of the patients remained alive, and 17% (n = 10) experienced a recurrence of symptoms. Angiography or ultrasound obtained at 14+/- 5 months after the procedure demonstrated a restenosis rate of 29% (n = 20). All patients with recurrent symptoms had angiographic in-stent restenosis and were successfully revascularized percutaneously.

CONCLUSIONS

Percutaneous stent placement for the treatment of CMI can be performed with a high procedural success and a low complication rate. The long-term freedom from symptoms and vascular patency are comparable with surgical results. The inherent lower procedural morbidity and mortality makes the endovascular approach the preferred revascularization technique for these patients.

N type Ca2+ channels and RIM scaffold protein covary at the presynaptic transmitter release face but are components of independent protein complexes

Fast neurotransmitter release at presynaptic terminals occurs at specialized transmitter release sites where docked secretory vesicles are triggered to fuse with the membrane by the influx of Ca2+ ions that enter through local N type (CaV2.2) calcium channels. Thus, neurosecretion involves two key processes: the docking of vesicles at the transmitter release site, a process that involves the scaffold protein RIM (Rab3A interacting molecule) and its binding partner Munc-13, and the subsequent gating of vesicle fusion by activation of the Ca2+ channels. It is not known, however, whether the vesicle fusion complex with its attached Ca2+ channels and the vesicle docking complex are parts of a single multifunctional entity. The Ca2+ channel itself and RIM were used as markers for these two elements to address this question. We carried out immunostaining at the giant calyx-type synapse of the chick ciliary ganglion to localize the proteins at a native, undisturbed presynaptic nerve terminal. Quantitative immunostaining (intensity correlation analysis/intensity correlation quotient method) was used to test the relationship between these two proteins at the nerve terminal transmitter release face. The staining intensities for CaV2.2 and RIM covary strongly, consistent with the expectation that they are both components of the transmitter release sites. We then used immunoprecipitation to test if these proteins are also parts of a common molecular complex. However, precipitation of CaV2.2 failed to capture either RIM or Munc-13, a RIM binding partner. These findings indicate that although the vesicle fusion and the vesicle docking mechanisms coexist at the transmitter release face they are not parts of a common stable complex.

Elevated Brain Natriuretic Peptide Predicts Blood Pressure Response After Stent Revascularization in Patients With Renal Artery Stenosis

Background— A significant number (20% to 40%) of hypertensive patients with renal artery stenosis will not have blood pressure improvement after successful percutaneous revascularization. Identifying a group of patients with refractory hypertension and renal artery stenosis who are likely to respond to renal stent placement would be beneficial.

Methods and Results— Brain natriuretic peptide (BNP) was measured in 27 patients with refractory hypertension and significant renal artery stenosis before and after successful renal artery stent placement. This neuropeptide was elevated (median, 187 pg/mL; 25th to 75th percentiles, 89 to 306 pg/mL) before stent placement and fell within 24 hours of the successful stent procedure (96 pg/mL; 25th to 75th percentiles, 61 to 182 pg/mL; P =0.002), remaining low (85 pg/mL; 25th to 75th percentiles, 43 to 171 pg/mL) at follow-up. Clinical improvement in hypertension was observed in the patients with a baseline BNP >80 pg/mL (n=22) in 17 patients (77%) compared with 0% of the patients with a baseline BNP ≤80 pg/mL (n=5) ( P =0.001). After correction for glomerular filtration rate, BNP was strongly correlated with improvement in hypertension.

Conclusions— BNP is increased in patients with severe renal artery stenosis and decreases after successful stent revascularization. In addition, an elevated baseline BNP level of >80 pg/mL appears to be a good predictor of a blood pressure response after successful stent revascularization.

Catheter-Based Treatment for Patients With Acute Ischemic Stroke Ineligible for Intravenous Thrombolysis

BACKGROUND AND PURPOSE

We present our single-center experience using catheter-based therapy for acute ischemic stroke patients who were not candidates for intravenous thrombolytic therapy.

METHODS

Neurologic outcomes were assessed in patients with acute ischemic stroke, ineligible for intravenous thrombolysis, treated with an emergent catheter-based therapy.

RESULTS

Nonparametric analysis of neurological outcomes demonstrated a benefit in National Institutes of Health Stroke Scale (NIHSS) at long-term follow-up (P=0.036). Independence in daily activities and improvement in NIHSS of > or =4 points were achieved in 38% and 56% of patients, respectively. Four patients (25%) died, including 2 patients (12.5%) who died from intracranial hemorrhage.

CONCLUSIONS

Catheter-based treatment offers a promising treatment strategy in patients with acute ischemic stroke ineligible for intravenous thrombolysis.

Percutaneous revascularization of the common femoral artery for limb ischemia

We performed percutaneous transluminal intervention in 20 consecutive patients (21 limbs) with common femoral artery (CFA) lesions causing symptomatic limb ischemia. In 12 limbs, concurrent additional percutaneous intervention proximal or distal to the target CFA lesion was performed. Angiographic success was obtained in 100%, with procedural success (angiographic success without a major in-hospital complications) in 90% and clinical success (procedural success and in-hospital improvement by at least one Fontaine functional class) in 81% of the limbs. The in-hospital Fontaine class improved by at least one functional class in 17 of 19 patients (89%), and the overall in-hospital event-free survival was 90% (18 of 20 patients). At follow-up (11.4 +/- 6 months), the overall event-free survival was 90% (18 of 20 patients) and 17 of 19 patients (89%) continue to show improvement by at least one functional (Fontaine) class. Percutaneous intervention of the CFA can be performed with a rate of high technical success and a low complication rate. It provides excellent clinical results at mid-term follow-up and appears to be a reasonable alternative to surgical therapy in patients at high risk for surgery.

Application of TAML catalysts to remove colour from pulp and paper mill effluents

A TAML catalyst (0.5 microM, 0.23 mg/L of effluent) combined with hydrogen peroxide (6.5 mM, 0.19 g/L of effluent) were capable of permanently removing 46% of the colour from bleach plant effluent (Eop, pine-derived) in one hour at 5,000 L effluent per day. Increasing concentrations to 2 microM catalyst (0.9 mg/L of effluent) and 22 mM peroxide (0.75 g/L of effluent), resulted in removal of 78% of the colour. In addition, 29% of the chlorinated organic material (AOX) was also removed. A laboratory investigation indicated that the oxidative process predominantly removed phenolic structures. The low aromatic content of the effluent meant that the majority of the organic material was not substantially altered during treatment. Thus chemical oxygen demand was essentially unchanged. This technology was able to remediate colour from effluents derived from both softwood (pine) and hardwood (eucalypt). Laboratory studies on catalyst life-time during effluent treatment, demonstrated that activity was maintained for a sufficient period to eliminate all the chromophore available to the active species, but that the catalyst did not survive long enough to be discharged into the receiving environment. Microtox tests showed that catalyst degradation products were not toxic to the receiving environment.

Treatment of coronary stent thrombosis with rheolytic thrombectomy: results from a multicenter experience

The objective of this study was to assess the feasibility, efficacy, and safety of rheolytic thrombectomy (RT) for treatment of coronary stent thrombosis. Stent thrombosis is an infrequent but potentially devastating complication. Conventional treatment with balloon angioplasty and/or thrombolysis has yielded suboptimal results. RT was used to treat 18 patients (mean age, 62 +/- 8 years; 72% male) with in-stent thrombosis (mean time to stent thrombosis, 2.4 +/- 1.8 days). Device success, procedure success, in-hospital and 30-day major cardiovascular events (MACE) were assessed in the hospital and at 30 days. Device success was obtained in 94% and procedure success was achieved in 100% of patients. Following RT, 11 patients underwent balloon angioplasty and 7 patients received additional stents. TIMI 3 coronary flow was obtained in 94.4% and all (100%) patients achieved either TIMI 2 or 3 coronary flow. The angiographic thrombus area decreased from 113.7 +/- 79 to 5.5 +/- 5.7 mm(2) after RT, and to 0.9 +/- 2.1 mm(2) (P < 0.001) after final treatment. Procedural complications were limited to transient no-reflow in five patients. Only one patient evolved a Q-wave MI. At 30 days of follow-up, no patients suffered death, emergent bypass surgery, or stroke. Our data suggest that the adjunctive use of rheolytic thrombectomy offers improved outcomes compared to prior results of intervention after coronary stent thrombosis and should be strongly considered as a treatment option for this complication.

Carotid stents to prevent stroke: a nonsurgical option

Angioplasty and stent placement have become accepted alternatives to surgery in many vascular territories. The most recent application of percutaneous intervention has been to explore its clinical utility and safety for stroke prevention in carotid arteries. Over the past 8 years, from January 1994 until Nov 2002, we performed 449 elective carotid stent procedures in 426 patients and in 481 vessels. Informed consent was obtained from each patient. Success was achieved in 97.3% of the patients treated. After one month of follow-up, 12 (2.8%) patients experienced stroke or death. After an average of 2.8 ± 1.7 years (range 1 month to 8.8 years) of follow-up, restenosis was found in 11 (2.6%) patients and was treated with balloon angioplasty. Our results, in a predominantly high-risk surgery group of patients, suggest that carotid stent placement is a viable treatment alternative to conventional surgery. It is likely that as the technology continues to evolve, the procedural risks of stroke and death will be minimized by embolic protection devices, making carotid stenting an option for low-risk surgical patients.

Carotid and cerebral angiography performed by cardiologists: cerebrovascular complications

The management of extracranial carotid artery disease is primarily concerned with the prevention of acute stroke. In order to understand the current risks of carotid angiography performed by interventional cardiologists, we undertook a retrospective study to determine the neurologic complications in patients who underwent selective cerebral angiography. All patients undergoing studies that were limited to diagnostic aortic arch angiography and selective four-vessel cerebral angiography in the cardiac catheterization laboratories during the past 6 years were included in this study. Hospital records were reviewed to determine any in-hospital cerebrovascular complications following carotid angiography, ranging from transient ischemic attack to major disabling stroke or death. A total of 189 consecutive patients underwent 191 diagnostic studies limited to aortic arch and four-vessel cerebral angiography in the cardiac catheterization laboratories between 1 January 1995 and 31 December 2000. Only one (0.52%) neurological complication, a minor stroke, occurred in our study population. There were no transient ischemic attacks, major strokes, or death. We have shown that experienced interventional cardiologists can perform diagnostic aortic arch and selective carotid and vertebral angiography in a cardiac catheterization laboratory with a very low complication rate. Because the risks of angiography add to those of revascularization of the carotid artery, the most highly skilled angiographer, regardless of primary specialty, should perform these studies.

Vertebral artery stenting

The safety and efficacy of endoluminal stenting in treating atherosclerotic vertebral artery disease was evaluated in 38 vessels in 32 patients. Indications for revascularization included diplopia (n = 4), blurred vision (n = 4), dizziness (n = 23), transient ischemic attacks (n = 4), drop attack (n = 1), gait disturbance (n = 1), headache (n = 2), and asymptomatic critical stenosis (n = 1). Success (< 20% residual diameter stenosis, without stroke or death) was achieved in all 32 patients (100%). One patient experienced a transient ischemic attack (TIA) 1 hr after the procedure. At follow-up (mean, 10.6 months), all patients (100%) were alive and 31/32 (97%) were asymptomatic. One patient (3%) had in-stent restenosis at 3.5 months and underwent successful balloon angioplasty. Endoluminal stenting of vertebral artery lesions is safe, effective, and durable as evidenced by the low recurrence rate. Primary stent placement is an attractive option for atherosclerotic vertebral artery stenotic lesions. Cathet Cardiovasc Intervent 2001;54:1-5.

Mitochondrial Ca(2+) uptake depends on the spatial and temporal profile of cytosolic Ca(2+) signals

Using confocal imaging of Rhod-2-loaded HeLa cells, we examined the ability of mitochondria to sequester Ca(2+) signals arising from different sources. Mitochondrial Ca(2+) (Ca(2+)mit) uptake was stimulated by inositol 1,4,5-trisphosphate (InsP(3))-evoked Ca(2+) release, capacitative Ca(2+) entry, and Ca(2+) leaking from the endoplasmic reticulum. For each Ca(2+) source, the relationship between cytosolic Ca(2+) (Ca(2+)cyt) concentration and Ca(2+)mit was complex. With Ca(2+)cyt < 300 nm, a slow and persistent Ca(2+)mit uptake was observed. If Ca(2+)cyt increased above approximately 400 nm, Ca(2+)mit uptake accelerated sharply. For equivalent Ca(2+)cyt increases, the rate of Ca(2+)mit rise was greater with InsP(3)-evoked Ca(2+) signals than any other source. Spatial variation of the Ca(2+)mit response was observed within individual cells. Both the fraction of responsive mitochondria and the amplitude of the Ca(2+)mit response were graded in direct proportion to stimulus concentration. Trains of repetitive Ca(2+) oscillations did not maintain elevated Ca(2+)mit levels. Only low frequency Ca(2+) transients (<1/15 min) evoked repetitive Ca(2+)mit signals. Our data indicate that there is a lag between Ca(2+)cyt and Ca(2+)mit increases but that mitochondria will accumulate calcium when it is elevated over basal levels regardless of its source. Furthermore, in addition to the characteristics of Ca(2+) signals, Ca(2+) uniporter desensitization and proximity of mitochondria to InsP(3) receptors modulate mitochondrial Ca(2+) responses.

Treatment of femoral artery pseudoaneurysm with percutaneous thrombin injection

Pseudoaneurysm formation of the femoral artery is a well-known complication following catheter-based vascular procedures. Ultrasound-guided compression or surgical correction are commonly used for its repair. We describe a new method of treatment for femoral pseudoaneurysm. The pseudoaneurysm is visualized by contralateral angiography and thrombosed with a percutaneous thrombin injection while the distal vessel is isolated with a brief balloon inflation. Fluoroscopically guided percutaneous thrombin injection is a promising, minimally invasive technique for the treatment of iatrogenic pseudoaneurysm, especially in patients with compromised distal circulation.

Global revascularization

Percutaneous endovascular intervention has revolutionized the treatment of peripheral vascular disease by allowing successful treatment of patients who are not good surgical candidates. Cardiologists with peripheral vascular training are more readily able to identify patients with concomitant peripheral arterial disease. It has been our experience that the technical skills necessary to perform coronary angioplasty are transferable to the peripheral vasculature. However, an understanding of the natural history of peripheral disease and of patient and lesion selection criteria, and the knowledge of other treatment alternatives are essential elements required to perform these procedures safely and effectively. There are inherent advantages for patients when the interventionalist performing the procedure is also the clinician responsible for the pre- and post-procedure care, analogous to the vascular surgeon who cares for patients before and after surgical procedures. In view of the increased incidence of coronary artery disease in patients with atherosclerotic peripheral vascular disease, the participation of a cardiologist in their care seems appropriate.

Provisional stenting for symptomatic intracranial stenosis using a multidisciplinary approach: acute results, unexpected benefit, and one-year outcome

Percutaneous techniques have dramatically changed our approach to coronary and peripheral revascularization. Intracranial atherosclerosis is a highly morbid disease; however, techniques for revascularization are still in evolution. The authors comprise a multidisciplinary team of neurologists, neuroradiologists, and interventional cardiologists who have collaborated in treating fifteen patients with symptomatic intracranial stenosis who have failed medical therapy. The acute success rate (100%) and one-year freedom from death and stroke (93.4%) using balloon angioplasty and provisional stenting are encouraging. A surprising observation in this patient cohort was that 53% of patients had improvement or resolution of a deficit that was chronic and presumed to be permanent and irreversible. This type of chronic but reversible deficit is termed "brain angina". The background, rationale for a multidisciplinary team, techniques, and preliminary results of intracranial angioplasty with provisional stenting are presented.

Percutaneous profundaplasty in the treatment of lower extremity ischemia: results of long-term surveillance

PURPOSE

To assess the procedural and long-term clinical outcomes of balloon angioplasty of the profunda femoris artery in patients with severe limb ischemia.

METHODS

Thirty-one consecutive patients were evaluated for severe ischemia in 32 limbs: 13 (41%) were categorized Fontaine class 2B, and 19 (59%) were class 3 or 4. The superficial femoral artery was occluded in 20 (62%) limbs; an additional vessel was treated in 22 (69%) limbs.

RESULTS

Procedural success was achieved in 91% (31/32) of limbs. The ankle-brachial index increased from 0.5 +/- 0.2 at baseline to 0.7 +/- 0.2 after intervention (p < 0.01). In-hospital limb salvage was 94% (30/32), and in-hospital event-free survival was 90% (28/31). At a mean follow-up of 34 +/- 20 months, no additional amputations were necessary; 3 patients required repeat revascularization, and 5 patients died. Freedom from revascularization was 88% in the 25 survivors. At follow-up, 88% of the patients had Fontaine class 1 or 2A symptoms, and only 12% had Fontaine class 2B or higher (p < 0.001 compared with baseline).

CONCLUSIONS

These data suggest that percutaneous profundaplasty is safe, effective, and may be considered as an alternative to surgical therapy in patients with anatomically suitable lesions.

Calcium signalling--an overview

Calcium (Ca2+) is an almost universal intracellular messenger, controlling a diverse range of cellular processes, such as gene transcription, muscle contraction and cell proliferation. The ability of a simple ion such as Ca2+ to play a pivotal role in cell biology results from the facility that cells have to shape Ca2+ signals in the dimensions of space, time and amplitude. To generate the variety of observed Ca2+ signals, different cell types employ components selected from a Ca2+ signalling 'toolkit', which comprizes an array of signalling, homeostatic and sensory mechanisms. By mixing and matching components from the toolkit, cells can obtain Ca2+ signals that suit their physiology.

A comparison of fluorescent Ca2+ indicator properties and their use in measuring elementary and global Ca2+ signals

Quantifying the magnitude of Ca2+ signals from changes in the emission of fluorescent indicators relies on assumptions about the indicator behaviour in situ. Factors such as osmolarity, pH, ionic strength and protein environment can affect indicator properties making it advantageous to calibrate indicators within the required cellular or subcellular environment. Selecting Ca2+ indicators appropriate for a particular application depends upon several considerations including Ca2+ binding affinity, dynamic range and ease of loading. These factors are usually best determined empirically. This study describes the in-situ calibration of a number of frequently used fluorescent Ca2+ indicators (Fluo-3, Fluo-4, Calcium Green-1, Calcium Orange, Oregon Green 488 BAPTA-1 and Fura-Red) and their use in reporting low- and high-amplitude Ca2+ signals in HeLa cells. All Ca2+ indicators exhibited lower in-situ Ca2+ binding affinities than suggested by previously published in-vitro determinations. Furthermore, for some of the indicators, there were significant differences in the apparent Ca2+ binding affinities between nuclear and cytoplasmic compartments. Variation between indicators was also found in their dynamic ranges, compartmentalization, leakage and photostability. Overall, Fluo-3 proved to be the generally most applicable Ca2+ indicator, since it displayed a large dynamic range, low compartmentalization and an appropriate apparent Ca2+ binding affinity. However, it was more susceptible to photobleaching than many of the other Ca2+ indicators.

Acute renal failure after redo thoracoabdominal aortic aneurysm repair in a patient with a solitary kidney: successful percutaneous treatment

PURPOSE

To report the successful percutaneous treatment of renal artery stenosis that precipitated renal failure following surgical repair of a thoracoabdominal aortic aneurysm (TAAA).

METHODS AND RESULTS

A 70-year-old woman with a solitary kidney became anuric 2 hours after urgent repair of a symptomatic true aneurysm of the Carrel patch from an 8-year-old TAAA repair. After medical treatment failed, aortography was performed, identifying complete occlusion of the solitary renal artery. Balloon dilation and implantation of a Palmaz stent restored renal perfusion and improved function. At 6-month follow-up, she was normotensive and her creatinine within normal limits.

CONCLUSIONS

Renal artery stenosis or occlusion is a treatable cause of acute renal failure after TAAA repair. Percutaneous treatment options are likely to be better tolerated than surgical revascularization in this patient population.

Global revascularization: the role of the cardiologist

There are compelling reasons for cardiologists to undertake a more global approach to patients with peripheral vascular diseases: atherosclerosis is a 'systemic' disease frequently causing both coronary and peripheral vascular problems in the same patient; coronary artery disease is the most common cause of morbidity and mortality in patients with peripheral vascular disease; and peripheral vascular disease negatively impacts the management of angina pectoris and congestive heart failure. There are four major areas of special interest to the cardiologist: (1) iliac arteries (vascular access), (2) renal arteries (hypertension and volume overload), (3) subclavian arteries (coronary steal with a left internal mammary artery [LIMA] graft), and (4) carotid arteries (stroke). Technical skills necessary to perform coronary angioplasty are transferable to the peripheral vasculature. However, an understanding of the natural history of peripheral disease, patient and lesion selection criteria, and knowledge of other treatment alternatives are essential to performing these procedures safely and effectively. Appropriate preparation and training, and a team approach, including an experienced vascular surgeon, are both desirable and necessary before interventional cardiologists who are inexperienced in the treatment of peripheral vascular disease attempt percutaneous peripheral angioplasty. There are inherent advantages for patients when the cardiologist performing the procedure is also a clinician. Judgments regarding the indications, timing, and risk/benefit ratio of procedures are enhanced by a long-term relationship between physician and patient. Finally, in view of the increased incidence of coronary artery disease in patients with atherosclerotic peripheral vascular disease, the participation of a cardiologist in their care seems appropriate.