High level of extracellular potassium and its correlates after severe head injury: relationship to high intracranial pressure

OBJECT: Disturbed ionic and neurotransmitter homeostasis are now recognized as probably the most important mechanisms contributing to the development of secondary brain swelling after traumatic brain injury (TBI). Evidence obtained in animal models indicates that posttraumatic neuronal excitation by excitatory amino acids leads to an increase in extracellular potassium, probably due to ion channel activation. The purpose of this study was therefore to measure dialysate potassium in severely head injured patients and to correlate these results with measurements of intracranial pressure (ICP), patient outcome, and levels of dialysate glutamate and lactate, and cerebral blood flow (CBF) to determine the role of ischemia in this posttraumatic ion dysfunction. METHODS: Eighty-five patients with severe TBI (Glasgow Coma Scale Score < 8) were treated according to an intensive ICP management-focused protocol. All patients underwent intracerebral microdialyis. Dialysate potassium levels were analyzed using flame photometry, and dialysate glutamate and dialysate lactate levels were measured using high-performance liquid chromatography and an enzyme-linked amperometric method in 72 and 84 patients, respectively. Cerebral blood flow studies (stable xenon computerized tomography scanning) were performed in 59 patients. In approximately 20% of the patients, dialysate potassium values were increased (dialysate potassium > 1.8 mM) for 3 hours or more. A mean amount of dialysate potassium greater than 2 mM throughout the entire monitoring period was associated with ICP above 30 mm Hg and fatal outcome, as were progressively rising levels of dialysate potassium. The presence of dialysate potassium correlated positively with dialysate glutamate (p < 0.0001) and lactate (p < 0.0001) levels. Dialysate potassium was significantly inversely correlated with reduced CBF (p = 0.019). CONCLUSIONS: Dialysate potassium was increased after TBI in 20% of measurements. High levels of dialysate potassium were associated with increased ICP and poor outcome. The simultaneous increase in dialysate potassium, together with dialysate glutamate and lactate, supports the concept that glutamate induces ionic flux and consequently increases ICP, which the authors speculate may be due to astrocytic swelling. Reduced CBF was also significantly correlated with increased levels of dialysate potassium. This may be due to either cell swelling or altered vasoreactivity in cerebral blood vessels caused by higher levels of potassium after trauma. Additional studies in which potassium-sensitive microelectrodes are used are needed to validate these ionic events more clearly.

High extracellular potassium and its correlates after severe head injury: relationship to high intracranial pressure

Disturbed ionic and neurotransmitter homeostasis are now recognized to be probably the most important mechanisms contributing to the development of secondary brain swelling after traumatic brian injury (TBI). Evidence obtained from animal models indicates that posttraumatic neuronal excitation via excitatory amino acids leads to an increase in extracellular potassium, probably due to ion channel activation. The purpose of this study was therefore to measure dialysate potassium in severely head injured patients and to correlate these results with intracranial pressure (ICP), outcome, and also with the levels of dialysate glutamate, lactate, and cerebral blood flow (CBF) so as to determine the role of ischemia in this posttraumatic ionic dysfunction. Eighty-five patients with severe TBI (Glasgow Coma Scale score < 8) were treated according to an intensive ICP management-focused protocol. All patients underwent intracerebral microdialyis. Dialysate potassium levels were analyzed by flame photometry, as were dialysate glutamate and dialysate lactate levels, which were measured using high-performance liquid chromatography and an enzyme-linked amperometric method in 72 and 84 patients respectively. Cerebral blood flow studies (stable Xenon--computerized tomography scanning) were performed in 59 patients. In approximately 20% of the patients, potassium values were increased (dialysate potassium > 1.8 mmol). Mean dialysate potassium (> 2 mmol) was associated with ICP above 30 mm Hg and fatal outcome. Dialysate potassium correlated positively with dialysate glutamate (p < 0.0001) and lactate levels (p < 0.0001). Dialysate potassium was significantly inversely correlated with reduced CBF (p = 0.019). Dialysate potassium was increased after TBI in 20% of measurements. High levels of dialysate potassium were associated with increased ICP and poor outcome. The simultaneous increase of potassium, together with dialysate glutamate and lactate, supports the hypothesis that glutamate induces ionic flux and consequently increases ICP due to astrocytic swelling. Reduced CBF was also significantly correlated with increased levels of dialysate potassium. This may be due to either cell swelling or altered potassium reactivity in cerebral blood vessels after trauma.

Comparison between intravitreal and orbital floor triamcinolone acetonide after phacoemulsification in patients with endogenous uveitis

PURPOSE: To compare the effect of intravitreal and orbital floor triamcinolone acetonide (TA) on macular edema, visual outcome, and course of postoperative inflammation after cataract surgery in uveitis patients. DESIGN: Prospective, randomized clinical trial. METHODS: Monocenter study (40 patients) with chronic endogenous uveitis who underwent phacoemulsification with intraocular lens implantation with either 4 mg intravitreal TA (n = 20) or 40 mg orbital floor TA (n = 20). The primary outcome was influence on cystoid macular edema (CME). Secondary outcome measures were best-corrected visual acuity (BCVA), anterior chamber cell grade, laser flare photometry, giant cell deposition, posterior capsule opacification (PCO), and intraocular pressure. RESULTS: Mean central foveal thickness decreased in the intravitreal TA group and increased in the orbital floor TA group (P < .001 at one and three months). CME improved in 50% of patients after intravitreal TA, whereas it was unchanged after orbital floor TA (difference between the groups at three months, P = .049). Mean BCVA (logarithm of the minimal angle of resolution) improved postoperatively (P < .001) from 0.76 and 0.74 to 0.22 and 0.23 in the intravitreal TA and orbital floor TA group, respectively. Anterior chamber cell count at one month was lower in the intravitreal TA than in the orbital floor TA group (P = .02). Laser flare photometry values and giant cell numbers were slightly higher after orbital floor TA than after intravitreal TA. The groups did not differ with respect to PCO rate and ocular hypertension. CONCLUSIONS: The CME improvement and anti-inflammatory effect after intravitreal TA was better than after orbital floor TA injection in cataract surgery in uveitis patients.

Percutaneous closure of a postinfarction ventricular septal defect and an iatrogenic left ventricular free-wall perforation using two Amplatzer muscular VSD occluders

A 83-year-old woman underwent percutaneous closure of postinfarction ventricular septal defect following anteroseptal myocardial infarction and percutaneous coronary intervention with stent implantation of the left anterior descending coronary artery. Postinfarction percutaneous ventricular septal defect closure was initially complicated by an iatrogenic left ventricular free-wall perforation. Both defects were closed using two Amplatzer muscular VSD occluders during the same session.

Transcatheter closure of patent foramen ovale with radiofrequency: acute and intermediate term results in 144 patients

AIMS: Currently available devices for transcatheter closure of patent foramen ovale (PFO) which rely on a permanent implant have limitations, including late complications. The study objective was to evaluate the safety, feasibility, and effectiveness of the PFx Closure System, the first transcatheter technique for PFO closure without an implantable device. METHODS AND RESULTS: A prospective study of 144 patients was conducted at nine clinical sites from October 2005 through August 2007. All patients had a history of cryptogenic stroke, transient ischemic attack, migraines, or decompression illness. The mean balloon stretched diameter of the PFO was 7.9 +/- 2.5 mm. Technical success (successful application of radiofrequency energy) was achieved in 130 patients. One patient required a transfusion as a result of blood loss during the procedure. There were no other major procedural complications. There were no recurrent strokes, deaths, conduction abnormalities, or perforations following the procedure. At a mean follow-up of 6 months, successful closure was achieved in 79 patients (55%). In PFOs with balloon sized or stretched diameters less than 8 mm, the closure rate was 72% (53/74). CONCLUSION: This study demonstrates that transcatheter closure of a PFO without a permanent implant is technically feasible and safe. Further technique and device modifications are required to achieve higher closure rates.

Successful percutaneous coronary intervention after implantation of a CoreValve percutaneous aortic valve

BACKGROUND: The association between aortic valve disease and coronary atherosclerosis is common. In the recent era of percutaneous aortic valve replacement (PAVR), there is little experience with coronary artery intervention after valve implantation. CASE REPORT: To our knowledge, this is the first case of successful percutaneous coronary intervention after implantation of a CoreValve percutaneous aortic valve. We report a case of a 79-year-old female patient who underwent successful coronary artery intervention few months after a CoreValve's percutaneous implantation for severe aortic valve stenosis. Verifying the position of the used wires (crossing from inside the self expanding frame) is of utmost importance before proceeding to coronary intervention. In this case, crossing the aortic valve, coronary angiography, and multivessel stenting were successfully performed. CONCLUSION: Percutaneous coronary intervention in patients with previous CoreValve is feasible and safe.

Tooth eruption: altered gene expression in the dental follicle of patients with cleidocranial dysplasia

OBJECTIVES The dental follicle plays an important role in tooth eruption by providing key regulators of osteogenesis and bone resorption. Patients with cleidocranial dysplasia (CCD) exhibit delayed tooth eruption in combination with increased bone density in the maxilla and mandible, suggesting disturbances in bone remodeling. The aim of this study was to determine the expression of genes relevant for tooth eruption and bone remodeling in the dental follicles of patients with CCD and normal subjects. MATERIAL AND METHODS Thirteen dental follicles were isolated from five unrelated patients with CCD, and fourteen dental follicles were obtained from 10 healthy individuals. All teeth were in the intraosseous phase of eruption. The expression of RANK, RANKL, OPG, and CSF-1 was determined by quantitative RT-PCR. RESULTS In patients with CCD, the mRNA levels of RANK, OPG, and CSF-1 were significantly elevated compared with the control group. Accordingly, the ratios of RANKL/OPG and RANKL/RANK mRNAs were significantly decreased in patients with CCD. CONCLUSION The observed alterations in the expression and ratios of the aforementioned factors in the dental follicle of CCD individuals suggest a disturbed paracrine signaling for bone remodeling that could be responsible for the impaired tooth eruption seen in these patients.

Unusual cause of myocardial infarction and congestive heart failure in a patient with prosthetic valve endocarditis

In a patient with staphylococcus lugdunensis prosthetic aortic valve endocarditis and coronary septic embolism accompanied by antero-lateral myocardial infarction, embolic material was successfully aspirated from the bifurcation of the left anterior descending coronary artery and the first diagonal branch. A good angiographic result was documented six months thereafter when the patient presented with a second complication, pulsatile compression of the left main coronary artery by an abscess cavity originating between the aortic and mitral annulus, leading to congestive heart failure. The patient underwent successful surgical replacement of the aortic valve prosthesis with concomitant patch reconstruction of the annulus as well as tricuspid annuloplasty.

One-year head to head comparison of the neointimal response between sirolimus eluting stent with reservoir technology and everolimus eluting stent: an optical coherence tomography study

OBJECTIVE to compare the vascular healing process between the sirolimus-eluting NEVO and the everolimus-eluting Xience stent by optical coherence tomography (OCT) at 1-year follow-up. BACKGROUND Presence of durable polymer on a drug-eluting metallic stent may be the basis of an inflammatory reaction with abnormal healing response. The NEVO stent, having a bioresorbable polymer eluted by reservoir technology, may overcome this problem. METHODS All consecutive patients, who received NEVO or Xience stent implantation between September 2010 and October 2010 in our institution, were included. Vascular healing was assessed at 1-year as percentage of uncovered struts, neointimal thickness (NIT), in-stent/stent area obstruction and pattern of neointima. RESULTS A total 47 patients (2:1 randomization, n = 32 NEVO, n = 15 Xience) were included. Eighteen patients underwent angiographic follow-up (eight patients with nine lesions for NEVO vs. 10 patients with 11 lesions for Xience). The angiographic late loss was numerically higher but not statistically different in NEVO compared with Xience treated lesions (0.38 ± 0.47 mm vs. 0.18 ± 0.27 mm; P = 0.171). OCT analysis of 4,912 struts demonstrated similar rates of uncovered struts (0.5 vs. 0.7%, P = 0.462), higher mean NIT (177.76 ± 87.76 µm vs. 132.22 ± 30.91 µm; P = 0.170) and in stent/stent area obstruction (23.02 ± 14.74% vs. 14.17 ± 5.94%, P = 0.120) in the NEVO as compared with Xience. CONCLUSION The NEVO stent with a reservoir technology seems to exhibit more neointimal proliferation as compared to Xience stent. The findings of our study, which currently represent the unique data existing on this reservoir technology, would need to be confirmed in a large population.

Amplatzer left atrial appendage occlusion: single center 10-year experience

OBJECTIVES To report a 10-year single center experience with Amplatzer devices for left atrial appendage (LAA) occlusion. BACKGROUND Intermediate-term outcome data following LAA occlusion are scarce. METHODS Short- and intermediate-term outcomes of patients who underwent LAA occlusion were assessed. All procedures were performed under local aesthesia without transesophageal echocardiography. Patients were discharged on acetylsalicylic acid and clopidogrel for 1-6 months. RESULTS LAA occlusion was attempted in 152 patients (105 males, age 72 ± 10 years, CHA2 DS2 -Vasc-score 3.4 ± 1.7, HAS-BLED-score 2.4 ± 1.2). Nondedicated devices were used in 32 patients (21%, ND group) and dedicated Amplatzer Cardiac Plugs were used in 120 patients (79%, ACP group). A patent foramen ovale or atrial septal defect was used for left atrial access and closed at the end of LAA occlusion in 40 patients. The short-term safety endpoints (procedural complications, bleeds) occurred in 15 (9.8%) and the efficacy endpoints (death, stroke, systemic embolization) in 0 patients. Device embolization occurred more frequently in the ND as compared to the ACP group (5 patients or 12% vs. 2 patients or 2%). Mean intermediate-term follow up of the study population was 32 months (range 1-120). Late deaths occurred in 15 patients (5 cardiovascular, 7 noncardiac, 3 unexplained). Neurologic events occurred in 2, peripheral embolism in 1, and major bleeding in 4 patients. The composite efficacy and safety endpoint occurred in 7% and 12% of patients. CONCLUSION LAA closure may be a good alternative to oral anticoagulation. This hypothesis needs to be tested in a randomized clinical trial to ensure that all potential biases of this observational study are accounted for.

New approach to direct stenting using a novel "all-in-one" coronary stent system via 5 French diagnostic catheters: a pilot study

OBJECTIVES We sought to evaluate the strategy success and short term clinical outcomes of direct stenting via 5 French (F) diagnostic catheters using a novel bare metal stent with integrated delivery system (IDS) (Svelte Medical Systems, New Providence, NJ) and compare the results to a conventionally treated matched group. METHODS Fifteen consecutive patients with lesions deemed suitable for direct stenting using a bare metal stent were included. The primary endpoint was the strategy success defined as the ability to successfully treat a target lesion via a 5 F diagnostic catheter with a good angiographic result (TIMI III flow, residual stenosis ≤20%). Procedure and fluoroscopy times, contrast agent use, cost, and short-term clinical outcomes were compared to a matched group treated via conventional stenting. RESULTS The primary endpoint was reached in 14/15 patients (93%). There were no significant differences in procedural (58.6 min ± 12.7 vs. 57.4 min ± 14.2) or fluoroscopy times (10.0 min ± 4.3 vs.10.1 min ± 3.9) or contrast agent use (193.7 ml ± 54.8 vs. 181.4 ml ± 35.6). However, there were significant reductions in materials used in the study group compared to the control group equating to cost savings of almost US $600 per case (US $212.44 ± 258.09 vs. US $804.69 ± 468.11; P = 0.001). CONCLUSIONS Direct stenting using a novel bare metal stent with an IDS via 5 F diagnostic catheters is a viable alternative to conventional stenting in selected patients and is associated with significant cost savings.