Can rotational atherectomy cause thermal tissue damage? A study of the potential heating and thermal tissue effects of a rotational atherectomy device

Cardiovasc Intervent Radiol 1998 Nov-Dec;21(6):481-6

Can rotational atherectomy cause thermal tissue damage? A study of the potential heating and thermal tissue effects of a rotational atherectomy device.

Gehani AA, Rees MR; Cardiac Research Unit, Killingbeck Hospital, Leeds, United Kingdom.

PURPOSE: Thermal tissue damage (TTD) is customarily associated with some lasers. The thermal potential of rotational atherectomy (RA) devices is unknown. We investigated the temperature profile and potential TTD as well as the value of fluid flushing of an RA device.

METHODS: We used a high-resolution infrared imaging system that can detect changes as small as 0.1 degree C to measure the temperature changes at the tip of a fast RA device with and without fluid flushing. To assess TTD, segments of porcine aorta were subjected to the rotating tip under controlled conditions, stained by a special histochemical stain (picrisirius red) and examined under normal and polarized light microscopy.

RESULTS: There was significant heating of the rotating cam. The mean "peak" temperature rise was 52.8 +/- 16.9 degrees C. This was related to rotational speed; thus the "peak" temperature rise was 88.3 +/- 12.6 degrees C at 80,000 rpm and 17.3 +/- 3.8 degrees C at 20,000 rpm (p < 0.001, t-test). Fluid flushing at 18 ml/min reduced, but did not abolish, heating of the device (11.8 +/- 2.9 degrees C). A crater was observed in all segments exposed to the rotating tip. The following features were most notable: (i) A zone of "thermal" tissue damage extended radially from the crater reaching adventitia in some sections, especially at high speeds. This zone showed markedly reduced or absent birefringence. (ii) Fluid flushing of the catheter reduced the above changes but increased the incidence and extent of dissections in the media, especially when combined with high atherectomy speeds. (iii) These changes were observed in five of six specimens exposed to RA without flushing, but in only one of six with flushing (p < 0.05). (iv) None of the above changes was seen in control segments.

CONCLUSION: RA is capable of generating significant heat and potential TTD. Fluid flushing reduced heating and TTD. These findings warrant further studies in vivo, and may influence the design of atherectomy devices.

Intraoperative thermographic monitoring during neurogenic thoracic outlet decompressive surgery

Vasc Endovascular Surg. 2003 Jul-Aug;37(4):253-7.

Intraoperative thermographic monitoring during neurogenic thoracic outlet decompressive surgery. 

Ellis W, Cheng S. Source Division of Vascular Surgery, University of Hong Kong Medical Center, Queen Mary Hospital, Hong Kong, China.

Abstract
This article reports the use of thermography to monitor 123 plexus decompressions for neurogenic thoracic outlet syndrome. The diagnosis and management of this disease continues to be controversial. Questions about pathologic mechanisms, the extent and frequency of muscular entrapment, scar, and interdigitations, as well as their relative contributions, remain. Thermographic visualization of the operated extremity allowed us to map and correlate thermal changes with specific surgical manipulations, as well as to analyze the tissues resected to better answer these questions. Initial thermal abnormalities indicating, usually, ulnar entrapments or irritation, normalized sequentially as discrete entrapments were resected. Thermographic monitoring continues to provide surgically useful information in one third of operations.

Possibility of the thermographic method for detection of ischemic myocardium

Possibility of the thermographic method for detection of ischemic myocardium.

Liakas R¹, Krishchiukaĭtis A, Iakushka P, Tsivinskene G, Veĭkutis V, Antushevas A, Vaĭchiulite R.

Author information

Abstract

Thermography (TG) is used as a contact free method for investigation of the myocardium ischemic injury. In coronary bypass surgery without artificial blood circulation it is important to know how cessation of blood supply affects the myocardium. In experiments on working heart, TG allows monitoring temperature at the desired point of the epicardium. The aim was to investigate relations between myocardial ischemia and temperature and to prove that the ischemic tissue and border zones can be determined by TG. Experiments were performed on mongrel dogs. In the areas of induced ischemia, ventricular surface thermograms (T) and electrograms (EG) were recorded. The obtained data showed that temperatures in ischemic area and border zone of myocardium were different from those in healthy myocardium. A detailed analysis of T of ischemic area showed that between ischemic and healthy myocardium a border zone is formed which is very important for arrhythmia genesis. The border zone is several millimeters wide, and its temperature is 1C higher than in healthy myocardium. The curve of the dynamics of temperature measured at all points of the ischemic zone has been created. Correlation between myocardium temperatures and characteristics of EG of ischemic zones is shown. 

Conclusion- The data show that TG is an appropriate method for determination of ischemic area and border zone in ventricular myocardium. TG gives a possibility to evaluate functional status of myocardium in a contact free way and may be applied for determination of ischemic damage of myocardium during cardiosurgery.

THERMOGRAPHY AS AN ADJUNCT WITH OTHER IMAGING MODALITIES TO EVALUATE THE PERFUSION OF FREEZING COLD INJURIES

THERMOGRAPHY AS AN ADJUNCT WITH OTHER IMAGING MODALITIES TO EVALUATE THE PERFUSION OF FREEZING COLD INJURIES

J.B. Mercer1, 2, J.E. Løkebø3 and L. de Weerd3

1Cardiovascular Research Group, Department of Medical Biology,

Faculty of Health Sciences, University of Tromsø, Tromsø, Norway.

2 Department of Radiology and

3Department of Plastic Surgery and Hand Surgery, University Hospital

of North Norway, Tromsø, Norway.

There is little international consensus on the management of freezing cold injuries (FCI) and treatment procedures vary from being aggressive (rapid amputation) to conservative (wait and see). The different approaches to treating such injuries can partly be explained by the complexity surrounding the injury. For example, with frostbite tissue freezing occurs which may involve only superficial tissues or may extend to the bone. The onset and severity of frostbite may be affected by a multitude of factors such as air temperature, wind speed, duration of exposure, amount of exposed area, and predisposing conditions such as poor or inadequate insulation from the cold or wind, immersion, altitude, impaired circulation from tight clothing or shoes, fatigue, injuries, circulatory disease, poor nutrition, dehydration, hypothermia, alcohol or drug use, and use of tobacco products. Damage to the frostbitten tissues is caused by crystallization of water within the tissues, typically between the cells, and by resulting changes in electrolyte concentration within the cells. Damage occurs during the freezing process. Further damage occurs during reperfusion of frostbitten tissue.Whatever the situation one of the key factors in recovery is adequate tissue blood perfusion. So whether one is interested in mapping the extent of such an injury in the acute phase or monitoring the effect of a treatment regime or assessing the final outcome, some form of blood perfusion measurement is desirable. An example of a multimodal imaging approach using CT angiography, MR, scintigraphy and thermography for investigating blood perfusion in a severe case of frost bite of the feet will be presented. It will be shown that thermography as a non-invasive method without the use of ionizing radiationwas helpful in confirming the diagnosis, assessing the severity of the injury, and finally monitoring the outcome of FCI.

Infrared thermography in the detection and management of coronary artery disease

Infrared thermography in the detection and management of coronary artery disease

It is unfortunate that for many men and women, the first sign or symptom of heart disease is a fatal heart attack. However, there is a technique that allows for early warnings using thermal imaging. A study in the American Journal of Cardiology concluded that, “Infrared thermography is a promising technique for the detection of CAD, before and after revascularization.”

One of the functions of the skin is autonomic temperature regulation by means of complex interactions controlled by the nervous system, which keeps our core temperature constant via micro-dermal circulation within the top layers of our skin. The study determined that asymmetrical patterns over the chest wall were valuable in alerting patients to suspected heart disease with 94 percent sensitivity.

Because everyone’s thermal fingerprint is incredibly stable over their lifetime, only when pathology of some type develops do asymmetrical patterns emerge, warning the patient and their physician that further testing needs to occur to determine the cause. With coronary artery disease (CAD), this warning can move the subject to action, often changing diet, exercise routines, stress management and other lifestyle modifications to stop or reverse the disease.

Along with cardiac imaging, other regions of the body can be imaged that indicate increased risk for development of CAD. Carotid arteries can be viewed to determine if there may be an occlusion (stroke assessment) or if, in the case of elevated CRP (blood marker for inflammation), it is determined that there is a lot of thermal activity in these arteries, a person’s risk of developing CAD is greatly increased. Besides carotid screening, dental health has now been determined to play a critical role in cardiac health.

Using this non-invasive screening method can offer men and women an opportunity for health monitoring and risk assessment. It uses no radiation and does not come in contact with the body. This technology is not typically covered by insurance, but is surprisingly affordable for most. DITI is the doorway to a new medical paradigm; one that empowers people to take responsibility for their overall health in an effort to prevent or reverse disease.