Intravascular ultrasound of normal left main arteries: Insights for stent optimization and standardization

• Left main (LM) lumen diameters >4 mm are the norm and diameter >4.5 mm is present in almost 50% of patients by intravascular ultrasound (IVUS).
• Normal LM minimum lumen area averages 14.1 mm² for women and 16.2 mm² for men, requiring an area stenosis of 57–63% for LM lesion to be hemodynamically significant using the prevailing criterion of 6 mm² as a cut‐off for revascularization.
• Incomplete LM visualization with IVUS is common (68%) without dedicated and specific LM IVUS techniques.

     

Vascular changes and black hole phenomenon after coronary brachytherapy: a pathologically distinct entity

Restenosis remains an important issue even after coronary brachytherapy despite its efficacy in the treatment for in-stent restenosis. The acute and chronic changes in vascular wall are unique following brachytherapy. The restenotic tissue post coronary brachytherapy is relatively acellular and appears echolucent in intravascular ultrasound examination. This is dubbed the "black hole" phenomenon. Despite the similarity in the mode of action of brachytherapy and drug eluting stent implantation, the black hole phenomenon seems to be uncommon after drug-eluting stent implantation except in those patients who have had prior brachytherapy, bare-metal placement and after treatment of saphenous venous graft stenosis. It is possible that not all neointima in stents are created equal. We should propose that neointima be considered primary neointima if it forms after bare metal stenting, secondary neointima if it forms after CBT or DES, and perhaps tertiary if after combined CBT and DES. This type of classification may prove useful for research or clinical purposes. Almost certainly black hole phenomenon results from a modified neointima. However, we do not know whether this is the same restenotic tissue that was present before CBT but just depleted of its cellular element secondary to autolysis or a newly formed tertiary neointima? It is also not clear whether the changes in vascular wall and restenosis are similar after CBT or drug-eluting stent placement. However, there are some unique vascular changes that seem to be common after both of these procedures.     

Long-term follow-up of brachytherapy for treatment of allograft in-stent restenosis.

The experience of brachytherapy in the treatment of in-stent restenosis of allograft arteries is limited. We present two cases of in-stent restenosis treated with brachytherapy with favorable angiographic follow-up at 10 months in one patient and at 17 months in the other.     

Human Y chromosome azoospermia factors (AZF) mapped to different subregions in Yq11

In a large collaborative screening project, 370 men with idiopathic azoospermia or severe oligozoospermia were analysed for deletions of 76 DNA loci in Yq11. In 12 individuals, we observed de novo microdeletions involving several DNA loci, while an additional patient had an inherited deletion. They were mapped to three different subregions in Yq11. One subregion coincides to the AZF region defined recently in distal Yq11. The second and third subregion were mapped proximal to it, in proximal and middle Yq11, respectively. The different deletions observed were not overlapping but the extension of the deleted Y DNA in each subregion was similar in each patient analysed. In testis tissue sections, disruption of spermatogenesis was shown to be at the same phase when the microdeletion occurred in the same Yq11 subregion but at a different phase when the microdeletion occurred in a different Yq11 subregion. Therefore, we propose the presence of not one but three spermatogenesis loci in Yq11 and that each locus is active during a different phase of male germ cell development. As the most severe phenotype after deletion of each locus is azoospermia, we designated them as: AZFa, AZFb and AZFc. Their probable phase of function in human spermatogenesis and candidate genes involved will be discussed.      

Determinants of acquisition of MR imaging units in an era of prospective payment

A survey was undertaken to examine the impact of Medicare's Prospective Payment System (PPS) and other recent changes in the health care environment on providers' decisions regarding acquisition of high-cost technologic equipment. The survey group included 199 hospitals and freestanding imaging centers known to have acquired magnetic resonance (MR) imaging units, as well as a random sample of 400 hospitals whose acquisition decisions were unknown to the authors. Fifty-eight percent of the known adopters and 61% of the randomly selected hospitals responded to the survey. Nonadopters' decisions were dominated by economic considerations, including the high cost of MR imagers and concerns about Medicare's reimbursement policies. Competition and a desire to provide the highest quality of care are counterbalancing the retardant effects of PPS, however, and are stimulating widespread diffusion of MR imagers.     

The degree of atherosclerosis in the descending aorta does not predict poor in-hospital outcome after surgery requiring cardiopulmonary bypass

OBJECTIVE: This study examined if the degree of atherosclerosis in the descending aorta is an independent predictor of poor in-hospital outcome for patients presenting for surgery involving cardiopulmonary bypass. DESIGN: The degree of atherosclerosis of the descending aorta was retrospectively reviewed in patients presenting for surgical procedures involving cardiopulmonary bypass from January 1, 2000, to December 31, 2003. Preoperative risk factors and in-hospital postoperative outcome parameters were obtained. SETTING: University teaching hospital. PARTICIPANTS: There were 310 consecutive patients enrolled in the study. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Two hundred forty-seven patients had coronary artery bypass grafting with or without valvular surgery, and 63 patients had isolated valvular surgery. The degree of atherosclerosis was rated as normal in 86 (28%), mild in 106 (34%), moderate in 69 (22%), and severe in 49 (16%) patients. Adjusting only for the degree of atherosclerosis, the total intensive care unit (ICU) time and the number of deaths were significantly higher in those patients with severe disease. Multivariable models adjusting for patients' risk factors showed a significant influence of atherosclerosis on total ICU time but not on other outcomes. The strongest predictor of poor outcome was a history of previous stroke (cerebral vascular accident). Other significant factors predicting poor outcome included previous coronary artery bypass surgery, a history of congestive heart failure, a history of dialysis, advanced age, and female sex. CONCLUSIONS: The degree of atherosclerosis in the descending aorta is not an independent predictor of poor in-hospital outcome after surgery involving cardiopulmonary bypass.