surgery at high altitude – Thoracic Surgery

High Altitude Surgery: Carotid Body Tumors

a different kind of case here at Cirugia de Torax

A Carotid paraganglion / carotid body tumor in Bogotá, Colombia

K. Eckland, ACNP-BC, MSN, RN & Ricardo Buitrago, MD

Case History: 62-year-old Hispanic female who presented with complaints of a right neck mass X 3 years, accompanied by occasional dysphagia, itching and soreness of right neck. Patient denied history of weight loss, anorexia, aspiration or recent pneumonias. No history of previous stroke.

Past medical / surgical history: TAH, 25 years prior, Hypertension, previous DVT of the RLE. Home medications: ASA 100mg po Q day.

On examination, the patient had a palpable, reducible mass over the right carotid, with no bruits on auscultation.

Diagnostics: carotid duplex showing a right-sided carotid body tumor arising at the bifurcation of the common carotid. No evidence of hemodynamically significant atherosclerotic plagues, or elevated velocities. Mass measured at 7cm at widest point.

Labs: All labs within normal limits including a Hgb 16/ Hct 48

Operative:

After administration of general anesthesia, and endotracheal intubation, the patient was positioned, prepped and draped in sterile fashion. A 4cm vertical skin incision was made on the right side of the neck. After blunt dissection and retraction of sternoclastomastoid muscle, the common carotid artery was identified and retracted with a vessel loop. Identifying the bifurcation and loosely clamped external and internal carotids. Care was taken to identify and prevent injury to the hypoglossal nerve and fascial branches.

Extensive ligation of tributary vessels was undertaken while performing blunt dissection to the avascular plane. Once the tumor was separated from the carotid bifurcation, it was removed and sent for final pathology.

At the conclusion of the case, a small jp drain was placed. The patient was awakened in the operating room and extubated. Patient demonstrated no new neurological deficits.

specimen — less than 5% of tumors are malignant

Post-operative:

JP drain was discontinued on the morning of POD#2 and the patient was subsequently discharged. Patient reported no dysphagia, hoarseness or paresthesia.

Discussion:

The carotid body serves as an important function of the detection and moderation of hypoxia. This has been shown in several studies of post-operative carotid endartectomy patients who are unable to adjust/ acclimatize to increasing altitude as well as the increased incidence of carotid body tumors (CBT) at altitudes of 2000 meters of greater (Ojeda Parades).

Carotid body tumors occur most frequently at altitudes greater than 2,500 meters but significant differences have been noted in the prevalence, size and other characteristics of carotid body tumors occurring at lower altitudes. The vast majority (95%) of these tumors are benign but in a minority of these cases, these tumors may represent metastatic disease.

Despite the location of these tumors, (at the bifurcation of the common carotid into the external and internal carotid), the chances for successful excision and resection is high with a mortality of less than 1%. The most common complication of this procedure is damage to the adjacent nerve, causing hoarseness.

References

Boedecker, C. C. (2011). Paragangliomas and paraganglioma syndromes. Head and Neck Surgery, 2011 (10). A nice review article of paragnaglions including paragrangliomas of the head and neck.

Cerecer – Gil, N. Y., Figuera, L. E., Llamas, F. J., et. al. (2010). Mutation of SDHB as a cause of hypoxia related high altitude paraganglion. Clin Cancer Res 2010; 16: 4148-4154. [free full-text pdf.]

Conde, S. V., Ribeiro, M. J., Obeso, A., Rigual, R., Monteiro, E. C., Gonzalez, C. (2012, recently published research). Chronic caffeine intake in adult rat inhibits carotid body sensitization produced by chronic hypoxia but maintains intact chemoreflex output. Molecular Pharmacology Fast Forward. 46 page report on animal study. [full-text available.]

Moore, J. P., Claydon, V. E., Norcliff, L. J., Rivera-Ch, M. C., Leon-Velarde, F., et. al. (2006). Carotid baroreflex regulation of vascular resistance in high-altitude andean natives with and without chronic mountain sickness. Experimental Physiology 91(5); 907-913. [free full-text pdf.]

Ojeda, L. P., Durango, E., Rodriquez, C., & Vivar, N. (1988). Carotid body tumors at high altitude: Quito, Ecuador, 1987. World J. Surg. 12: 856- 860.

Park, S. J., Kim, Y. S., Cho, H. R. & Kwon, T. W. (2011). Huge carotid body ganglion. J Korean Surg Soc 2011; 81: 291- 294. Case report. [free full text pdf available.]

Rodriguez – Cuervasm S., Lopez – Garcia, J. & Labastida – Alemandro, S. (1998). Carotid body tumors in inhabitants of altitudes higher than 2000 meters above sea level. Head & Neck, Aug 1998: 374-377. [free full-text pdf available.]

Authors conducted a study of 120 CBT in Mexico City, D.F looking at the incidence and characteristics of all CBTs over a thirty year period (1965 – 1995) in comparison to previously published reports of CBT at lower altitude. Findings similar to previous and existing literature with a predominantly female population (89% of cases). Mean age 49. Mean size 5.4 cm. They reported a 20% incidence of cranial nerve injury after resection.

Ruben, R. J. (2007). The history of the glomus tumors nonchromaffin chemodectoma: a glimpse of biomedical Camelot. Acta Oto-Laryngeologica 2007; 127: 411-416. If you can get past his fanciful writing style which resembles an ardent love letter, the article gives a nice history of paraganglion tumors (including carotid body tumors).

Talking about carotid body tumors at XXIX Congreso Latinamericano de Cirugia Vascular y Angiologia

talking about the incidence of carotid body tumors at altitude with the world’s experts

This is not one of our usual topics here but since carotid body tumors (CBT /carotid paraganglion) are often associated with increased altitude; we are pleased to bring more information about the condition from several of Latin America’s experts from Quito, Ecuador, Mexico City (D.F.), Bogotá, Colombia and La Paz, Bolivia. (Also given the level of expertise in this room, on this specialized condition – it would be almost criminal not to report this information.)

We have requested copies of the powerpoint presentations to include here, so please check back soon.

Dr. Oscar Ojeda Paredes, MD – email: oscarle19@hotmail.com

discussed the incidence, presentation, diagnosis and treatment in Quito. He also discussed the different characteristics in carotid body tumors occurring at altitude versus sea level. While carotid body tumors have a genetic component related to abnormal mutations of Chromosome 11, tumors according at sea level occur more frequently in familial patterns and reach larger sizes. The majority of patients seen at altitude are less than 3 cm, and asymptomatic in nature with the exception of a palpable mass. (This mimics the case presented here at CdeT.)

Several of the cases were in young females (less than 40 years). Dr. Ojeda and Dr. Guerrero explained that this believed to be related to the increased incidence of hypoxia during pregnancy (due to hemodilution and vascular expansion) in women with the chromosomal mutation.

Powerpoint presentation: Tumores del Cuerpo Carotídeo Experiencia ecuatoriana (All content is the property of Dr. Ojeda).

During a separate presentation, Dr. Ojeda also addressed the rare complication of ‘Syndrome of Insufficient Baroreflex’

This sydrome occurs after the afferent fibers serving the carotid sinus are damaged during surgery (usually for the removal of carotid body tumors.) The syndrome occurs most frequently in patients who have had bilateral surgery – and while uncommon is not limited to patients who undergo carotid body tumor resection – it has also been reported in the literature in carotid endarterectomy patients.

Dr. Valente Guerrero, MD (Mexico City, D.F). – email: valentecv@prodigy.net.mx

Dr. Valente discussed the incidence of carotid body tumors in Mexico City. Despite being at the lowest altitude of the respective cities – given the very large surrounding population – Dr. Valente reports a significant number of cases in his hospital, as well as the results of several studies conducted in Mexico City. As mentioned in the literature, Dr. Guerrero (and the other presenting surgeons) report a very low incidence of malignacy.

Dr. Alberto Munoz, MD – National Cancer Institute (NCI) in Bogota, Colombia

Dr. Munoz reports that while the majority of these cases are referred to Head & Neck (ENT) surgeons – there is a fairly significant incidence of disease in Bogotá, with surgeons at the National Cancer Institute seeing 30 cases in 2008, and 48 cases in 2009. (If you’ve read some of the other literature, you’ll realize this is a larger sample that frequently reported – for example one study reported only 120 cases over a 30 year period.)

Dr. Munoz reports that at his facility 8 – 10% of these tumors occur bilaterally, and are found of 10 – 12% of all carotid ultrasounds performed at NCI. Dr. Munoz also reviewed the existing the existing body of literature, dating back to 1963 – which is surprisingly small (total of seven studies with a total 412 tumors – including a previous study with a 160 patients in Bogotá.)

Dr. Ivan Soto Vaca- Guzman, MD (La Paz, Bolivia) Email: isotovacaguzman@yahoo.com

Dr. Soto presented information regarding several of his cases, including a discussion of previous Bolivian publications on carotid paraglanglion, as well as more recent data from his institution. This included a total of 467 patients with 134 patients (2005 – 2012). In comparison with much of the previously presented data – in Dr. Soto’s experience and research, the majority of patients developed CBT on the left. Similar to the other presenters the majority of patients were asymptomatic, and intra-operatively were found to have a Shamblin classification of II.

His most recent work confirmed the previously demonstrated predilection for females – with a female to male ratio of 8:1.

He also discussed the use of a pre-operative grading system based on ultrasound results based on the Shambling classification system is limited as it is a surgical classification applied at the time of surgery. He discussed a new classification system, called UPEC developed by Dr. Alvaro Balcazar, Dr. Lopez and Dr. Ivan Soto, Bolivian vascular surgeons. The advantages of Balcazar’s classification system is the prediction of complications – since tumors with extensive invasion into adjacent structures have a much higher risk of significant (and potentially life-threatening) bleeding. Dr. Soto states that he rarely, if ever, needs to embolize the tumor prior to surgical removal.

The UPEC classification system – uses letters A – D to indicate the amount of tumor invasion.

Stage A: without invasion

Stage B: partial invasion – partial invasion into the carotid only.

Stage C: Extensive invasion – may extend laterally, or into cephalic or caudal areas.

Stage D: Compromise of neighboring structures.

More about the study and the UPEC system:

Balcazar, A., Lopez, C. & Soto, I. (2011). Tumor del cuerpo carotideo de altura. Revision de 35 anos. Conceptos actuales, manejo de 333 tumors y nuevo clasificacion. Technicas endovasculares XIV (3): 3929 – 3939. (page 40 of on-line document).

But what about Tibet?

One of the questions addressed at the conference was the absence of carotid body tumors in places such as Tibet (at significant elevation). However, these differences are theorized to related to the chromosomal mutations that cause carotid hyperplasia in response to hypoxia. So while hypoxia certainly exists at Mount Everest – people (particularly women) carrying this mutation may not.

Protected: Register to participate in high altitude research project

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Research update: Recruiting interested surgeons

Cirugia de Torax extends an invitation to all thoracic surgeons interested in participating in clinical research.

If you are interested in participating in our data collection process as a site investigator – please click on the link to fill out one of our secure, encrypted Site Investigator Applications. While we are strongly recruiting surgeons from areas of moderate to high altitude, we are encouraging interested surgeons from any location to consider participating.

Why participate?

As busy surgeons, many of you just don’t have the time to devote to full-time research, academic projects and scholarly writing. That doesn’t mean you aren’t interested in, and can not make a significant contribution to the literature surrounding topics in thoracic surgery. By signing up as a site investigator, you (or your delegates) will use our new electronic applications to upload and submit de-identified data about your patient populations and outcomes for use in our study. (It’s like the STS general thoracic database – but easier!)

In return, you will have made a significant and lasting contribution to the existing body of knowledge in your chosen specialty, and will receive due credit in all subsequent articles and publications based on these contributions.

Fill out my form!

Mexican Surgeons: See you at the conference in Cancun..

Sociedad Mexicana de Neumologia y Cirugia de Torax

Cirugia de Torax.org heads south of the border for the upcoming Sociedad Mexicana de Neumologia y Cirugia de Torax congreso (conference) this April. It’s also a chance for surgeons to find out more about the high altitude project.

The title of this post is apt in more ways that one. The Mexican Society of Pulmonologists and Thoracic Surgeons is meeting for their 2012 annual meeting this April, and yes, Cirugia de Torax.org is going to be there. We’re hoping to interview and talk to some of Mexico’s greatest innovators and researchers in thoracic surgery during our visit this year.

We will be also talking about the high altitude lung surgery project with interested and potential participants – including prospective timelines, data collection tools (and validity of measurements), and expected responsibilities/ duties of site participants.

This year’s conference is being held in Cancun, from April 9th thru April 13th, 2012. Check back in April for more news and conference coverage.

Surgery at altitude, part I

Calling all thoracic surgeons – particularly those in La Paz, Quito, Bogota and Mexico City.. We have an opportunity for collaborative research.

One of our newest endeavors is a research project on thoracic surgery at moderate altitude. We’ve completed our review of existing literature, and developed our patient parameters and data collection points.

The main base of our operations is Flagstaff, Arizona, which is located at 7000 ft. (2,000 meters) making it the highest altitude cardiothoracic program in the United States. The Flagstaff site has several strengths in that much of our patient population comes from the surrounding areas; which are located at both higher and lower elevations. However, one of the weaknesses in Flagstaff is our small patient population – as a single surgeon site devoted to both cardiac and thoracic surgery – our lung surgery volumes are fairly small.

Right now, I am doing some of the preliminary work with the hospital – meeting with staff to apply for IRB approval, and formalizing the data collection process. I am also interested in recruiting surgeons from other sites to participate in data collection. Dedicated thoracic surgeons with large thoracic surgery practices would be ideal – and all results will be published and presented by surgeon/ and site.

We are particularly interested in recruiting surgeons from the following areas:

1. La Paz, Bolivia

2. Quito, Ecuador

3. Bogotá, Colombia

4. Mexico City, DF – Mexico

These four cities combined house many millions of people living at moderate altitudes, and would help provide for a wider and more expansive collection of data on patients undergoing thoracic surgery. Demographic differences (such as pre-existing thoracic diseases, incidence of heavy cigarette smoking, etc.) of geographic locales will also allow for further points of comparison.

Please contact Cirugia de Torax if you are interested in participating. All participating surgeons and institutions will receive credit (in accordance to level of participation) in any and all subsequent professional and scientific publications.

You can also contact me, K. Eckland, directly at : k.eckland@gmail.com. Please place ‘cirugia de torax’ or ‘altitude project’ in the sibject line.

High Altitude Surgery, part I

As our writer returns to moderate altitude in the foothills of the Andes, we take a look at the published research related to altitude illnesses and surgery.

This seemed like a timely entry here at Cirugia de Torax, as I return from Bogotá, Colombia (the third highest capital city in the world.) However, while the concept of surgical constraints due to elevation is not new; but today we will discuss definitions and explore the published literature. I’d also like to apologize to my readers – much of the available medical literature in not available as a free text, so while I am able to access and reference this information – I can not post links to the full articles themselves.

First, we need to define some terms when we talk about altitude, since most of the research is actually looking at very high (versus moderate altitude). This is important because as you will see, very few people are living at, and even fewer people are having surgery at these heights.

Definitions of Altitude: from Muzo, Tulco & Cymerman (2004).

Very-High Altitude: 4250 – 6000 meters elevation (13,943 ft to 19,685 ft): There are few permanent cities at this altitude. At the upper range of very high altitude cities, you are essentially talking about ‘base camp’ settlements of Mount Everest and places like Wenzhuan (Tibet) which is listed as the world’s highest city at an elevation of 16,467. (There is some controversy over this status, as La Riconada, Peru at 16,728 ft. (5100 meters) also claimed status as the highest city. There are no cities with any significant size (greater than just a few thousand residents) at this elevation. However, the majority of altitude research has been conducted at the very high and high altitude elevations.

High-Altitude: 2500 meters – 4249 meters
(8,202 ft to 13,940 ft): this classification includes several larger cities / population centers including three capital cities:

La Paz, Bolivia (est. elevation ranging from 3200 meters to 3,650 meters in different portions of the city) population of metro area: 2.3 million.

Quito, Ecuador (est. elevation 2800 meters or 9186 feet) population: 1.4 million

Bogotá, Colombia (2660 meters, 8727 feet) population: 10 million

According to the majority of scientific and medical literature, physiological adaptation, high altitude effects and illnesses usually do not occur until people reach an altitude of 2500 meters or greater. (However, the authors acknowledge that in certain individuals – these effects can occur at relatively low elevations (1,000 meters).

Moderate Altitude: 1000 meters to 2500 meters (3900 feet to around 8000 ft) This is actually the level that most of the people who are concerned about the effects of elevation live and operate at. This includes Denver, Colorado; Lake Tahoe, California/Nevada; Flagstaff, Arizona and several other American cities in the Sierra Nevada Mountain Range. It also includes several Alpine cities (while the alps themselves are around 4400 – 4800 meters, most of the cities are in the valleys, and most lay at around 1500 meters.)

Low Altitude: below 1000 meters.

References:

Heart. 2006 Jul;92(7):921-5. Epub 2005 Dec 9. Safety and exercise
tolerance of acute high altitude exposure (3454 m) among patients with coronary artery disease. Schmid JP, Noveanu M, Gaillet R, Hellige G, Wahl A, Saner H. (Switzerland)

Chest. 1995 Nov;108(5):1292-6. The safety of air transportation of
patients with advanced lung disease. Experience with 21 patients requiring lung transplantation or pulmonary thromboendarterectomy. Kramer MR, Jakobson DJ, Springer C, Donchin Y. (Israel).

Br J Sports Med. 1995 Jun;29(2):110-2. Poor ventilatory response to mild hypoxia may inhibit acclimatization at moderate altitude in elderly patients after carotid surgery. Roeggla G, Roeggla M, Wagner A, Laggner AN. (Austria).

Thorax. 1995 Jan;50(1):22-7. Doppler assessment of hypoxic pulmonary vasoconstriction and susceptibility to high
altitude pulmonary oedema. Vachiéry JL, McDonagh T, Moraine JJ, Berré J, Naeije R, Dargie H, Peacock AJ. (Belgium)

Ann Surg. 1897 Sep;26(3):297-306. II. A Preliminary Comparison
of Methods and Results in Operative Surgery at the Sea Level (New York) and in Places of High Altitude (Denver). Powers CA. (Note the date of publication – 1897 – we’ve been looking at this issue for quite a long time.)

West J Med. 1995 Aug;163(2):117-21. Sea-level physical activity and acute mountain sickness at moderate altitude. Honigman B, Read M, Lezotte D, Roach RC. – This is an interesting study which looks (observational by survey only) at the physiological responses of conference participants from low elevations upon reaching higher elevations (3000 meters in this study / 9,840 ft). The study compared the incidence of altitude sickness/ symptoms among people who defined themselves as physically fit/ physically active (using standardized criteria) versus more sedentary individuals. In total, 28% of the 200+ participants reported three or more symptoms of acute mountain sickness, but surprisingly, there was no difference in incidence among the physically fit (at sea-level) group and the more sedentary group which belies much of the current folklore related to altitude sickness.

Muza, Tulco & Cymerman (2004). Altitude Acclimatization Guide.

Essenbag, V., Halabi, A. R., Churchill-Smith, M & Lutchmedial, S. (2003). Air transport in Cardiac Patients. Chest 2003 Nov; 124(5): 1937-45. McGill University, Montreal, Canada.

Altitudes of World Cities – there are some discrepancies with altitudes listed here and other reference materials.

The 25 Highest US cities

In our next post we will talk more about this research, what it means, and what research is still needed to examine the effects of high altitude surgery, particularly in thoracic patients.