Takashi Miyamoto

The Usefulness of a 10% Air-10% Blood-80% Saline Mixture for Contrast Echocardiography: Doppler Measurement of Pulmonary Artery Systolic Pressure

OBJECTIVESnWe assessed an air-blood-saline mixture for Doppler measurement of pulmonary artery systolic pressure (PASP) and the mechanism of enhancement of the Doppler signal by this mixture.nnnBACKGROUNDnUnderestimation of PASP by Doppler echocardiography occurs with inadequate continuous wave (CW) signals of tricuspid regurgitation (TR).nnnMETHODSnWe assessed in vitro the diameter and concentration of microbubbles of agitated air-saline mixture, air-blood-saline mixture and 10% air-10% plasma-80% saline mixture immediately, 5, 10 and 20 s after agitation. In 20 patients, PASP was estimated by Swan-Ganz catheter and CW Doppler of TR: 1) without contrast injection; 2) with intravenous injection of 10% air-90% saline; and 3) 10% blood-10% air-80% saline mixture.nnnRESULTSnCompared to air-saline, addition of blood or plasma to the air-saline solution significantly increased the concentration of microbubbles (p < 0.001). The air-blood-saline (26.7 +/- 7.2 microm) and air-plasma-saline mixture (25.3 +/- 7.4 microm) had smaller microbubbles than air-saline mixture (31.6 +/- 8.2 microm) (p < 0.001). The correlation between Doppler- and catheter-measured PASP at baseline (r = 0.64) improved with agitated air-saline (r = 0.86). With the air-blood-saline mixture, the correlation further improved (r = 0.92) and the best limits of agreement were obtained.nnnCONCLUSIONSnThe combination of the patients own blood is a method of making a sterile solution of numerous small microbubbles for injection into the right-sided cardiac chambers. Clinically, the air-blood-saline mixture is easily prepared at bedside and is superior to the air-saline mixture in assessing PASP in patients with inadequate CW Doppler signals.

Coronary vasodilation by noninvasive transcutaneous ultrasound: An in vivo canine study

OBJECTIVESnWe evaluated the coronary vasodilatory effects of transcutaneous low-frequency (27-kHz) ultrasound (USD).nnnBACKGROUNDnUltrasound has been shown to affect vascular function.nnnMETHODSnUltrasound energy was administered transcutaneously to 12 dogs. Coronary arterial dimensions were assessed using intravascular coronary ultrasound (IVUS) and quantitative coronary angiography (QCA).nnnRESULTSnThe IVUS mid-left anterior descending (LAD) luminal area was 6.77 +/- 1.27 mm(2) at baseline. After 30 s of ultrasound, this area increased by 9% (7.40 +/- 1.44 mm(2), p < 0.05), after 3 min by 19% (8.05 +/- 1.72 mm(2), p < 0.05) and after 5 min increased by 21% (8.16 +/- 1.29 mm(2), p < 0.05). The mean coronary diameter (2.69 +/- 0.33 mm) at baseline (QCA of three segments of LAD and three segments of left circumflex coronary artery) increased by 19.3% (3.21 +/- 0.28 mm) after 5 min of USD exposure. After a 90-min observation period there was a return to baseline values (p = NS). Intracoronary nitroglycerin (NTG) administered to five dogs revealed a similar magnitude of vasodilation as USD.nnnCONCLUSIONSnNoninvasive, transthoracic low-frequency USD energy results in coronary artery vasodilation within seconds of exposure. The vasodilation is reversible and is similar in magnitude to that induced by NTG. Further evaluation is needed to assess its potential applications in humans.

Correlation of echo-Doppler aortic valve regurgitation index with angiographic aortic regurgitation severity

We assessed aortic regurgitation (AR) severity by utilizing multiple echo-Doppler variables in comparison with AR severity by aortic root angiography. Patients were divided into 3 groups: mild, moderate, and severe. An AR index (ARI) was developed, comprising 5 echocardiographic parameters: ratio of color AR jet height to left ventricular outlet flow diameter, AR signal density from continuous-wave Doppler, pressure half-time, left ventricular end-diastolic diameter, and aortic root diameter. There was a strong correlation between AR severity by angiography and the calculated echo-Doppler ARI (r = 0.84, p = 0.0001). As validated by aortic angiography, the ARI is an accurate reflection of AR severity.

Noninvasive transcutaneous ultrasound augments thrombolysis in the left circumflex coronary artery—an in vivo canine study

BACKGROUNDnUltrasound has the potential to augment chemical thrombolysis.nnnMETHODS AND RESULTSnThrombotic occlusions in the left circumflex artery (LCx) were induced in 27 dogs. Sixty minutes later, tissue-type plasminogen activator (t-PA) was given intravenously over 90 min. Thrombotic occlusions (n = 20) were treated with concomitant transcutaneous low frequency (27 kHz), continuous wave (CW) (n = 10) or pulsed wave (PW) (n = 10) ultrasound. Tissue-type plasminogen activator plus ultrasound (n = 20) vs. tissue-type plasminogen activator alone (n=7) resulted in more frequent Thrombolysis in Myocardial Infarction (TIMI) 3 flow (90% vs. 43%, P = 0.024) and less reocclusion (11% vs. 67%, P = 0.080). At 60 min, median TIMI grade flow for tissue-type plasminogen activator alone was 2 (mean: 1.43 +/- 1.40) compared to 3 (mean: 2.70 +/- 0.95) for tissue-type plasminogen activator plus continuous as well as pulsed wave ultrasound (P = 0.035). Continuous wave and pulsed wave ultrasound were equally effective in augmenting thrombolysis. Histologically, no ultrasound-mediated injury to the myocardium or coronary arteries occurred.nnnCONCLUSIONnBoth transcutaneous low frequency continuous wave ultrasound and pulsed wave ultrasound enhance tissue-type plasminogen activator-mediated thrombolysis of the posterior circulation with higher TIMI 3 flow rates and less reocclusion than with tissue-type plasminogen activator alone. In addition, at the energy levels used, low frequency ultrasound appears safe.

Multiple aortic valve papillary fibroelastoma: An unusual presentation of a rare tumor

Cardiac papillary fibroelastoma is a rare cardiac tumor and occurs mainly on cardiac valves. The incidence of multiple lesions is exceedingly rare and is about 7% of all reported cases. Careful echocardiographic evaluation of the patient before operation is of high importance as the there is no recurrence after surgical excision. We present the first case of a patient with multiple aortic valve papillary fibroelastomas diagnosed before operation. The patient underwent surgical removal of the 3 masses that were confirmed as cardiac papillary fibroelastomas by pathologic examination. There was no evidence of aortic insufficiency after operation.

Superiority of 10% air–10% blood–saline mixture for measuring the velocity of tricuspid regurgitation in patients with severe emphysema

BACKGROUNDnSevere emphysema frequently is associated with elevated pulmonary artery systolic pressure. However, it is often difficult to obtain adequate tricuspid regurgitation (TR) signals for measurement of pulmonary artery systolic pressure in patients with severe emphysema.nnnPURPOSEnThis study was conducted to evaluate the usefulness of air-blood-saline mixture in measuring TR velocity in severe emphysema.nnnMETHODSnWe studied 82 patients with severe emphysema (67.7 +/- 9.2 years, 57 males) who had no or mild TR on color Doppler. Contrast echocardiography studies were performed with agitated 10% air-90% saline and 10% air-10% blood-80% saline mixtures. Tracing quality and peak velocity were assessed on baseline continuous wave signals and contrast continuous wave signals with the 2 mixtures.nnnRESULTSnWith the injection of an air-saline mixture, the quality of TR tracing improved in 45 patients (P <.0001) and a higher peak TR velocity was obtained (2.46 +/- 0.37 m/s vs 2.95 +/- 0.40 m/s, P <.0001) compared with baseline echocardiography. Compared with air-saline mixture, the air-blood-saline mixture further enhanced TR tracing quality in 17 patients (P <.0001) and the peak TR velocity increased to 3.13 +/- 0.42 m/s (P <.0001).nnnCONCLUSIONSnIn patients with severe emphysema, an air-blood-saline mixture improves the quantifiable TR signals for more accurate estimation of pulmonary artery systolic pressure, even when there is minimal valve TR.

Synergism of aspirin and heparin with a low-frequency non-invasive ultrasound system for augmentation of in-vitro clot lysis.

AbstractBackground: Aspirin, glycoprotein IIb/IIIa inhibitors and heparin are routinely used in acute coronary syndromes. Previously we showed that there is synergism between ultrasound and heparin and tirofiban in augmenting blood clot disruption. However, there is a little data on a possible synergism of low-frequency ultrasound with aspirin for in-vitro clot dissolution, and especially on the combination of aspirin with heparin and/or glycoprotein IIb/IIIa inhibitors.nMaterials and Methods: Human blood clots (n = 320) were incubated for 10 or 20 minutes in saline containing aspirin alone or combined with heparin and/or tirofiban and/or eptifibatide. Clots were randomly treated with low-frequency ultrasound (27.3 kHz) or incubation only. The percent clot weight loss and the incremental effect of ultrasound were calculated.nResults: The most significant incremental effect of ultrasound on clot weight reduction was detected with aspirin alone (5.2 ± 2.3% and 5.2 ± 2.6% after 10′ and 20′, p = 0.04 and p = 0.06, respectively) and in combination with heparin (8.8 ± 2.5% and 11.5 ± 2.7% after 10′ and 20′, p = 0.01 and p = 0.0001, respectively). The greatest absolute magnitude of clot weight reduction was observed with ultrasound combined with aspirin and heparin (48.5 ± 9.5% after 20′). The addition of tirofiban or eptifibatide to aspirin, heparin and ultrasound did not increase clot lysis. However, eptifibatide had significantly better synergism than tirofiban (p = 0.025 and p = 0.015, after 10 and 20 minutes, respectively).nConclusions: Aspirin alone or in combination with heparin results in significant augmentation of clot lysis and is synergistic with application of low-frequency ultrasound for 10 and 20 minutes only. These results may have important implications for a possible use of low-frequency ultrasound in treatment algorithms of acute coronary syndromes.