经胸壁超声心动检查应用合理但价值有限

根据合理使用标准，一项单中心回顾性研究中的535例患者接受的经胸壁超声心动检查(TTE)有92%属于“合理应用”。然而，仅有32%的患者的治疗因TTE结果而发生了积极变化。这项研究发表在7月22日《美国医学会杂志-内科学》在线版上(JAMA Intern. Med. 2013 July 22 [doi:10.1001/jamainternmed.2013.8972])。

德克萨斯大学西南医疗中心的Susan A. Matulevicius医生报告称，近半数(47%)患者在TTE检查后仍然维持当前治疗，其余21%的患者的治疗没有任何变化。“合理性与临床意义之间的矛盾非常明显，提示目前实施的合理使用标准指南不太可能促进TTE使用的优化。”


Susan Matulevicius医生

在过去10年间，TTE的使用量已经翻倍，已占到所有心脏影像学服务的一半，相当于每年超过11亿美元的Medicare支出。Matulevicius医生指出，美国心脏病学会(ACC)、美国超声心动学会(ASE)和其他专业组织早在2007年就制订了合理使用标准(J. Am.Coll. Cardiol. 2007;50:187-204)，并在2011年时对其进行了更新(J. Am. Soc. Echocardiogr. 2011;24:229-67)。然而迄今为止，尚无大型研究评估这一标准的效果，也尚未确定TTE结果本身是否对临床诊疗产生了实质性影响。

Matulevicius医生及其同事回顾分析了2011年4月份他们所在医院实施的所有TTE的电子病历，以评估这些检查的合理性和对临床的影响。研究人群中59%为女性，平均年龄为58岁。大约55%的受试者为白人，21%为黑人，8%为西班牙裔。

2名普通心脏科专家在不了解TTE结果和患者临床过程的情况下，相互独立地对535次TTE进行了分析，根据最新的合理使用标准将其分为“合理”(91.8%)、“不合理”(4.3%)或“不确定”(3.9%)。另外2名心内科专家在不了解分类的情况下，相互独立地评估了每次TTE对临床的影响，将其分为“引起积极的治疗改变”(32%)、“继续现行治疗”(47%)或“未引起治疗改变”(21%)。

仅有32%的TTE结果引起了临床治疗的积极变化。最常见的变化是采取进一步诊断性检查(29%)和亚专科会诊(26%)。此外，合理TTE引起临床治疗变化的比例(32%)与不合理TTE引起临床治疗变化的比例(22%)并无显著差异。

研究者还进行了一项探索性分析，根据审查TTE的心脏科专家的共识，判断引起积极变化的TTE是否非常有价值、或者一般、或者无用，甚至属于误用。结果显示，仅有19%的TTE被认为“非常有价值”或“有价值”。另有6%的TTE被视为“无用”或“误用”。多数TTE(约占75%)被划为“一般”。

上述发现与既往其他机构开展的小型研究的结果一致，提示合理使用标准未能对临床医生的决策制定产生巨大影响，也未能遏制TTE使用量的大幅增长。

“本项研究显示，我们医院在1个月内就有114次TTE对临床治疗没有任何影响，1年就是1,300多次。假如其他医院也是如此，那么每年Medicare为超声心动检查支付的11亿美元中就有21%(相当于2.3亿美元)是无意义的。我们必须找到更好的办法来识别TTE很可能无意义的患者或情境。”

研究者指出，当前一些常见指征被认为是合理的但却对临床治疗影响很小，这类指征是需要重点关注的。“例如，对有理由怀疑瓣膜或结构性心脏病的患者进行初步评估(合理使用标准34)，对正在接受心脏毒性药物治疗的患者进行连续再评估(合理使用标准91)，是最常见的‘合理’TTE指征，但仅有不到15%可引起临床治疗的积极变化。”

“替代策略，包括限制超声心动检查和血浆生物标志物(例如敏感性肌钙蛋白和利钠肽的水平)筛查的使用，可能有助于改善TTE的使用效率。”

该研究获得了德克萨斯大学、国立转化科学推进中心和国立卫生研究院的支持。研究者无相关利益冲突披露。

随刊述评：“无变化”不等于治疗水平低

密歇根大学安阿伯分校医疗中心心脏科的William Armstrong医生和Kim A. Eagle医生在随刊述评中指出，这项研究值得赞赏，但将一次TTE简单地定性为“未引起临床治疗的变化”或者“维持现行治疗”可能会产生误导。这种描述会暗示读者，TTE结果被完全忽视了(JAMA Intern. Med. 2013 July 22 [doi:10.1001/jamainternmed.2013.7273])。

在这项研究中，有24例正在接受心脏毒性药物治疗的患者接受了TTE，其中21例患者在TTE后仍然维持现行治疗。然而，虽然治疗并未改变，但对这些患者继续进行TTE筛查却是非常合理、有益的。

同样的，TTE“是唯一能证实可疑肺高压存在与否的现实手段”。假如在TTE检查中未发现之前担忧的肺高压，那么“治疗无变化”就是完全合理的。

Armstrong医生和Eagle医生报告称无相关利益冲突。

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By: MARY ANN MOON, Cardiology News Digital Network

Transthoracic echocardiography was deemed to have been "appropriate" according to appropriate use criteria in nearly 92% of 535 cases in a single-center retrospective study reported online July 22 in JAMA Internal Medicine.

However, the TTE findings led to an active change in care in only 32% of those cases. In nearly half (47%) of cases, the TTE results resulted in simple continuation of current care, and there was no change in care for the remaining 21% of cases, said Dr. Susan A. Matulevicius and her associates at the University of Texas Southwest Medical Center, Dallas.
 
"The discrepancy between appropriateness and clinical impact is striking and suggests that the appropriate use criteria guidelines as currently implemented are unlikely to facilitate optimal use of TTE," the investigators noted.

The use of TTE has doubled during the past decade and now comprises half of all cardiac imaging services among Medicare beneficiaries. That represents more than $1.1 billion of the total Medicare expenditures for diagnostic imaging during one year, they said.

The American College of Cardiology, American Society of Echocardiography, and other professional groups developed appropriate use criteria for TTE in 2007 (J. Am.Coll. Cardiol. 2007;50:187-204) and updated them in 2011 (J. Am. Soc. Echocardiogr. 2011;24:229-67), but to date, no large study has assessed whether these efforts, or indeed whether the TTE results themselves, actually affect clinical care. Dr. Matulevicius and her colleagues said.

They reviewed the electronic health records for all TTEs performed during 1 month (April 2011) at their medical center, to assess the appropriateness and the clinical impact of the procedures.

The study population was 59% female and 41% male, and the mean age was 58 years. Approximately 55% of the subjects were white, 21% were black, and 8% were Hispanic.

Two general cardiologists who were blinded to the TTE results and to the patients’ clinical course independently reviewed the 535 cases, classifying them as appropriate (91.8%), inappropriate (4.3%), or uncertain (3.9%), according to the updated appropriate use criteria.

Two other noninvasive cardiologists who were blinded to these classifications independently assessed the clinical impact of each TTE and categorized the results as prompting an active change in care (32%), a continuation of current care (47%), or no change in care (21%).

The results of the TTE prompted an active change in clinical care in only 32% of cases. The most common changes were further diagnostic testing (29% of cases) and subspecialty consultation (26%), Dr. Matulevicius and her associates said (JAMA Intern. Med. 2013 July 22 [doi:10.1001/jamainternmed.2013.8972]).

In addition, there was no significant difference between the proportion of appropriate TTEs that led to a change in clinical care (32%) and the proportion of inappropriate TTEs that led to a change in clinical care (22%).

The researchers also conducted an exploratory analysis to determine, by consensus of the reviewing cardiologists, whether the TTEs that led to active change had been very useful, useful, neutral, not useful, or misused as guides to patient care.

Only 19% of all TTEs were judged to be very useful or useful. Another 6% were deemed not useful or misused. The majority (about 75%) were categorized as neutral in this analysis.

These findings are in line with those of previous small studies at other institutions. They suggest that the appropriate use criteria have failed to have much impact on physician decision making and have not curbed the massive growth of TTE use, the investigators added.

"In our study, 114 TTEs in 1 month led to no change in care, which equates to more than 1,300 TTEs on an annual basis. If our findings are corroborated in other settings and centers, 21% (or $230 million) of the $1.1 billion of Medicare expenditures on echocardiography could have been saved if these TTEs had not been performed.

"Better metrics for identifying patients or scenarios when TTE is likely to result in no change in care must be developed," they said.

Certain common indications that at present are considered to be appropriate but have minimal impact on clinical care should be targeted. "For example, initial evaluation of reasonably suspected valvular or structural heart disease (appropriate use criteria 34) and serial reevaluations in a patient undergoing therapy with cardiotoxic agents (appropriate use criteria 91) were the most common "appropriate" TTE indications but resulted in active change in care in fewer than 15% of studies.

"Alternative strategies, including performance of limited echocardiography or screening with plasma biomarkers, such as sensitive troponin and natriuretic peptide levels, may help to improve efficiency of TTE screening for these indications," Dr. Matulevicius and her associates said.

This study was supported by the University of Texas, the National Center for Advancing Translational Sciences, and the National Institutes of Health. No relevant financial conflicts of interest were reported.

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'No change' doesn’t mean poor care

This study is commendable, but simply designating a TTE as leading to no change in clinical care or to a continuation of existing care can be misleading. These descriptions imply that there was a total disregard for or ignorance of the TTE results, said Dr. William Armstrong and Dr. Kim A. Eagle.

In this study, TTE was performed in 24 patients receiving cardiotoxic agents, and the response to the TTE results was to continue existing care in 21 of them. But even though management did not change, continued TTE screening represents highly appropriate and highly beneficial state-of-the-art care for such patients, they noted.

Similarly, TTE is "the only realistic method for confirming the presence or absence" of suspected pulmonary hypertension. When this disorder is a legitimate concern but is not found to be present on TTE scanning, "no change" in care is entirely appropriate, Drs. Armstrong and Eagle said.

Dr. Armstrong and Dr. Eagle are in the division of cardiology at the University of Michigan Medical Center, Ann Arbor. They reported no financial conflicts of interest. These remarks were taken from their invited commentary accompanying Dr. Matulevicius’s report (JAMA Intern. Med. 2013 July 22 [doi:10.1001/jamainternmed.2013.7273]).