William D. Dockery

Pseudohypocalcemia after magnetic resonance imaging with gadolinium in patients with cirrhosis

Hypocalcemia in patients with cirrhosis may be due to a number of causes. We noted a relationship between injection with gadodiamide, a particular gadolinium chelate, during magnetic resonance imaging of the liver and the development of a falsely low serum total calcium level in a patient with cirrhosis. A cross‐reference and retrospective chart review identified 10 additional patients in whom this phenomenon was noted. We describe the temporal relationship and clinical characteristics of these patients. Pseudohypocalcemia following magnetic resonance imaging with gadodiamide contrast should be considered in the differential diagnosis of hypocalcemia in patients with cirrhosis. (Liver Transpl 2004;10:136–140.)

Utility of cardiac computed tomography for inflow cannula patency assessment and prediction of clinical outcome in patients with the HeartMate II left ventricular assist device

OBJECTIVES Proper inflow cannula orientation during implantation of the HeartMate II (HMII) left ventricular assist device (LVAD) is important for optimal pump function. This article describes our experience with cardiac computed tomography (CCT) to evaluate inflow cannula patency and predict future adverse outcomes (AE) after HMII LVAD implantation. METHODS Ninety-three patients underwent HMII LVAD implantation for end-stage cardiomyopathy from January 2010 until March 2014. A total of 25 consecutive patients had CCT after the implantation; 3 patients were excluded from the analysis due to associated abnormality of the outflow graft. The 22 patients with CCT after HMII LVAD were censored for adverse events related to LVAD malfunction after HMII LVAD implantation. The maximum percentage of inflow cannula obstruction on CCT was recorded. We analysed the predictive value of CCT in addition to other clinical and diagnostic variables for future AEs. RESULTS Seven of the 22 patients (32%) experienced AEs after HMII LVAD implantation. The degree of inflow cannula obstruction was higher in the group of patients who experienced an AE (70 vs 14%; P < 0.001). Inflow cannula obstruction >30% showed excellent correlation with AE longitudinally based on receiver operating curve (0.829). The group with AEs more frequently experienced CHF symptoms (P = 0.054). CONCLUSIONS Inflow cannula obstruction >30% on CCT predicts future adverse events in patients with HMII LVAD; the need for surgical intervention in terms of LVAD exchange or urgent listing for heart transplantation should be considered in good surgical risk patients. Cardiac computed tomography should be considered routinely postoperatively in patients with HMII LVAD.

Computed tomographic coronary angiography: experience at Baylor University Medical Center/Baylor Jack and Jane Hamilton Heart and Vascular Hospital

Noninvasive cardiac computed tomographic imaging using multislice or electron beam technology has been shown to be highly specific and sensitive in diagnosing coronary heart disease. It is about a fifth of the cost of coronary angiography and is particularly well suited for evaluating patients with a low or low to moderate probability of having obstructive coronary atherosclerosis. In addition, it offers more information than calcium scoring: because of the intravenous contrast used, it temporarily increases the density of the lumen and allows differentiation of soft plaque from calcified plaque. The Baylor Hamilton Heart and Vascular Hospital now uses this modality to define coronary atherosclerosis in patients who would otherwise have needed invasive coronary angiography; several research protocols with the technique are also under way. Baylor has recently upgraded to the 64-slice scanner. It is expected that computed tomographic coronary angiography will replace a significant percentage of invasive cardiac catheterizations.

Patency of Vein Graft Anastomoses Facilitated With the Hexalon Device

PURPOSE The Hexalon system (Castlewood Surgical, Inc, Dallas, TX) is a new device that facilitates a clampless, hand-sutured, vein-to-aorta anastomoses in no-touch off-pump coronary artery bypass surgery. Hexalon-facilitated anastomoses are structurally equivalent to traditional sutured anastomoses, but can be placed during off-pump coronary artery bypass surgery. It follows that these facilitated anastomoses would show similar patency rates to traditional sutured anastomoses. This is the first published data validating mid-term patency of Hexalon-facilitated anastomoses. DESCRIPTION Evaluation of bypass grafts by cardiac computed tomography angiography is highly accurate and has increasingly been used to assess graft patency in anastomotic device feasibility trials. We studied 15 proximal Hexalon-facilitated anastomoses for patency in 10 patients at least 6 months after off-pump coronary bypass surgery using gated cardiac computed tomography angiography. EVALUATION All 15 facilitated anastomoses were patent. All 10 CT studies were of sufficient quality for accurate interpretation. CONCLUSIONS The Hexalon system is a new and potentially valuable tool in advancing off-pump coronary artery bypass surgery.

Superiority of Computed Tomography Coronary Angiography Over Calcium Scoring to Accurately Evaluate Atherosclerotic Disease in a 35-Year-Old Man

A 35-year-old man with juvenile onset diabetes mellitus presented with exertion-associated chest pain. His risk factors also included smoking, hyperlipidemia, and strong family history. As part of a research protocol, he received a calcium score as well as multislice (computed tomography [CT]) coronary angiography using a new, 16-slice scanner (Lightspeed 16, GE Systems). There was no detectable epicardial coronary calcium (Figure 1). However, his noninvasive coronary angiogram demonstrated a high-grade stenosis in his mid-left anterior descending artery (LAD) (Figure 2 and Figure 3⇓). Additionally, there was a significant amount of plaque burden noted in the proximal LAD …

Critical left main coronary artery stenosis diagnosed by computed tomographic coronary angiography.

A 60-year-old man with previous cerebrovascular accident, hypercholesterolemia, and tobacco use presented with a several-month history of worsening exertional dyspnea. Immediate catheterization was considered unsafe, as the patient was taking warfarin (international normalized ratio, 2.9), and nonemergent, as the patients symptoms were relatively stable. Warfarin was stopped, and multislice computed tomographic coronary angiography (CTCA) was performed (Lightspeed 16, GE Systems) after obtaining appropriate consent. CTCA demonstrated a high-grade narrowing at the ostium of the left main coronary artery (Figure ​(Figure1,1, arrowheads). The ostium of the left main coronary artery had a tapered appearance and a large plaque in its ostial and proximal portions (Figure ​(Figure1b,1b, black arrow). A large amount of plaque was seen in all coronary distributions. Figure 1 Computed tomographic coronary angiogram demonstrating critical left main coronary artery stenosis. (a, b) The multiplanar reformat views clearly demonstrate a high-grade stenosis (arrowheads). (b) The plaque contains both soft and calcified components ... Cardiac catheterization was performed using a 4F system in an attempt to avoid excessive trauma to the artery. In addition, an intraaortic balloon pump and console were positioned inside the cardiac catheterization suite. Invasive coronary angiography demonstrated a critical stenosis of the left main coronary artery (Figure ​(Figure2,2, arrowhead), with pressure damping upon engagement of the 4F Judkins left catheter. The intraaortic balloon was placed, and the patient went on to have successful 5-vessel coronary artery bypass grafting that afternoon. Figure 2 Conventional invasive angiography confirmed the critical stenosis (arrowhead). CTCA allowed us to “preview” the coronary anatomy in a patient whose invasive catheterization was delayed due to anticoagulation. Demonstration of the critical stenosis prior to the catheterization allowed us to change the timing of the catheterization (which was originally planned for the next week) as well as the strategy. Normally, 6F catheters would have been used, which might have been more traumatic given the severity of the ostial left main artery stenosis. In addition, foreknowledge of the severity of the stenosis allowed us to plan for likely intraaortic balloon insertion.